User:Tomruen/archive4

= 2010 comments =

Jan 2009 Picture of the month at the Maths portal
In the usual way these things happen I volunteered to do the Math Portal's Picture of the month, and used one of yours. Thanks for making such great pictures ! -- John Blackburne (words ‡ deeds) 00:26, 4 January 2010 (UTC)

On the E8 Petrie
> I reverted usage of the new (right) image. I think the bright colors are distracting, and it's not clearly correct, seeing the inner circle lines are different. Tom Ruen (talk) 05:33, 4 January 2010 (UTC)

Retrieved from "http://en.wikipedia.org/wiki/User_talk:Jgmoxness"

Tom, While there is probably more to your change than "distracting colors", let's take comments in the talk section to get other opinions on whether distracting or beautiful.

Saying "it's not clearly correct" is also innaccurate. I would be happy to share the code so you can understand. As you know, the image that was there previously (as well as other Petrie representations don't actually display all 6720 sqrt(2) length edges (due to it becoming a smudge of lines near the center). The lines near the center will always look different based on aesthetics of where to cut off edge drawing (mine at 60%).

> ...no evidence new image is correct, compare to http://www.wired.com/table_of_malcontents/2007/03/e8_visualizing_/

Why did you use this reference? You really should reference more of the source material. Vogan's representation has a clear explanation of his aesthetic decisions as compared to Stembridge. 

Jgmoxness (talk) 13:56, 4 January 2010 (UTC)


 * I am NOT aware that "As you know, the image that was there previously (as well as other Petrie representations don't actually display all 6720 sqrt(2) length edges". I've only computed the hypercube family (like File:Hypercube_petrie_polygons.png) myself and would never imagine any reason for excluding edges being drawn NOR any reason to believe lines were missing in the original File:E8_graph.svg. I have Coxeter's book Regular Complex Polytopes with a drawing by McMillian and it looks like the original graph within my perception. Tom Ruen (talk) 21:33, 4 January 2010 (UTC)
 * ok, sorry for my assumptions. Coxeter/McMullen didn't have the compute power and doing it by hand would obviously necessitate more constrained aesthetic choices. While I give due credit to our founders - we need to stand on their shoulders without being constrained by their context. On a related note: I am surprised at the AIM website's droll text only representation that only the inner circle of mathematical intelligentsia can appreciate.  There is so much beauty in the hyper-dimensional symmetry of this E8 stuff - why are we quibbling over the aeshetics of one particular 2D projection (albiet quite exceptional). Going to 3D and using animation over varying edge lengths (norm'd 8D or 2/3D projected)...not to mention potentially interesting vertex assignments based on theoretical physics. What a great time to be doing this stuff. Sorry, I digress....

Jgmoxness (talk) 02:02, 5 January 2010 (UTC)

Thanks for your thoughts. I originally asked User:Rocchini to reproduce the McMillian figure for wikipedia, so that's what he did! It looks like it has 28 edges/vertex (rather than full set of 56!!) Now knowing it is incomplete, I'd like to get something else in the wikipedia article, perhaps a set of figures to show all the edges? On a related note, there's no images to the quasiregular polytopes of the E8/E7 families: Gosset_2_41_polytope, Gosset_1_32_polytope, Gosset_1_42_polytope. Can you construct these polytopes and related Petrie projections? I've not had time to try, or at least Rocchini blew me away with his quick work, but then he got busy too! Tom Ruen (talk) 02:23, 5 January 2010 (UTC)

BCE
Hi Tom. You shouldn't have made those changes at Template:Solar eclipses. I've seen that page for a while now and it was always using BC. Looks like you've messed up some more. Other pages for eclipses in pre-history now have titles that conflict with text when it comes to dates. I tried to move one back but messed it up myself. Hiro. —Preceding unsigned comment added by Hiro Miyake (talk • contribs) 21:27, 15 January 2010 (UTC)


 * Please explain more. Give me an example what is messed up. Tom Ruen (talk) 21:30, 15 January 2010 (UTC)
 * OK, at Eclipses 20th Century BCE we have BCE in the title but all the dates in the text use just BC.
 * Sure, that needs to be updated also for consistency. Tom Ruen (talk) 21:35, 15 January 2010 (UTC)
 * Nope. I've just read the Manual of Style, and according to that you don't change these notations. If it's BC then stick with it "unless you get broad agreement" and vice versa. I don't see any agreement for your changes, or any discussion. Hiro —Preceding undated comment added 22:05, 15 January 2010 (UTC).


 * My goal was consistency with source usage. The SOURCE is NASA, which uses either negative dates, or BCE, like . I've added the same to lunar eclipses, like List of 20th century BCE lunar eclipses. Tom Ruen (talk) 22:09, 15 January 2010 (UTC)


 * Ah, you've found Fred Espanak's personal preference. How about this or this . Nasa doesn't have a policy. Anyways, there's no need to change according to the guidelines. It winds people up (like me). Hiro Miyake (talk) 22:26, 15 January 2010 (UTC)


 * Well, I'm glad you're interested in having opinions. We're agreed there's different opinions and no right answer. What's next? MY ISSUE actually is I plan to replace those century tables when I get a chance, since they generate very slowly in my browser, peg out my CPU for minutes!!! Tom Ruen (talk) 22:33, 15 January 2010 (UTC)

NowCommons: File:SE1954Jun30T.png
File:SE1954Jun30T.png is now available on Wikimedia Commons as Commons:File:SE1954Jun30T.png. This is a repository of free media that can be used on all Wikimedia wikis. The image will be deleted from Wikipedia, but this doesn't mean it can't be used anymore. You can embed an image uploaded to Commons like you would an image uploaded to Wikipedia, in this case:. Note that this is an automated message to inform you about the move. This bot did not copy the image itself. --Erwin85Bot (talk) 20:47, 17 January 2010 (UTC)

Complex icosidodecahedrons
Since you seem to be very interested in polyhedra, could you help with small complex icosidodecahedron and great complex icosidodecahedron? Thanks. 4 T C 03:28, 24 January 2010 (UTC)

Prince Rupert
Hello. Maybe you would know how best to remedy the "orphaned" status of the stubby new article titled Prince Rupert's cube. Michael Hardy (talk) 05:00, 25 January 2010 (UTC)


 * I added a reference to Mathworld, and linked in cube, unsure whese else! Tom Ruen (talk) 06:24, 25 January 2010 (UTC)

Octahemioctahedron image
Which image more accurately reflects the properties of oho, the one with 2 colours (octahedral symmetry) or the one with 3 colours (tetrahedral symmetry)? OK, I know this has been raised before. 4 T C 05:38, 30 January 2010 (UTC)


 * The Wythoff construction uses Th symmetry, while the figure itself has Oh. I'd go with the construction (Th), but its an opinion. Tom Ruen (talk) 05:44, 30 January 2010 (UTC)

MAths rating
I noticed you added the maths rating template to a few articles without filling in the quality, priority, and field ratings. The only purpose of the template is to carry that data, so please remember to take a second to fill it in whenever you place the template on a talk page. &mdash; Carl (CBM · talk) 23:22, 30 January 2010 (UTC)

Congratulations
Hi Tomruen, Im very glad of the work you have been doing on higher dimension polytopes.

Im a programmer and my dream is to know how to create the code for a higher dimension polytope like 20-simplex. But i fell like its a unreachable magical hidden knowledge.

Im writing congratulate you and ask you if you could develop you polytopes images in SVG. Im asking this cause with SVG you can zoom in as much as you can and change the width of the lines, so you can learn the more about polytopes with a great detail.

is there any technical issue on the creation of SVG files?

Before i leave i must ask you one more thing : can you share the code of some polytopes so i can learn from it and create 3d projections of some polytopes (with advanced rendering, with shadows and shaders) and distribute it free on wikipedia?

Thanks , Mateus Zica --Mateus Zica (talk) 12:34, 31 January 2010 (UTC)

Hi Mateus!

Thank you for your kind words. I'd like to do SVG, and I've tried modifying the files made by others, but I've not really looked to see the format setup, so I've just been doing screen captures from my program. I know SVG has lots of power, so things like good choice of line-width and transparency takes work to look good.

I use Borland Delphi 3.0 (pascal) language Windows for my experimenting codes. I'd share my source by email if you had Delphi.

My codes really pretty simple, started with regular simplex/orthoplex/hypercubes, so coordinates pretty easy. The Petrie polygon projection took a bit more of linear algebra, to compute an orthogonal view basis. Then recently I also added truncated/rectified forms by more algebraic operations (rectified X has vertices at mid-edges of X).

If you're a programmer (and can generate SVG) perhaps you could write me some pseudo code to set up nice drawings, and I could just use that? (I'm lazy, just wanted to get some graphs up as I could!) Never enough time! Really I should be doing nothing now, but inspired to try!

If you want to help more, if you understood the Coxeter-Dynkin diagrams, how to extract facets, you could help expands tables at uniform polyteron. I got started, but gets tedious. I thought of writing a program also, but that's work too!

Also for help the vertex figures (at Talk:Vertex_figure/polychoron) are hand-drawn (in MSPaint) and could be improved by SVG versions. There's a LOT for the uniform and 4-polytope and honeycombs! (The 5-polytope ones still probably could use some improvements before SVG, partly done at Talk:Vertex_figure/polyteron)

What do you think?

Tom Ruen (talk) 12:52, 31 January 2010 (UTC)

Rocchini has some example code in description File:Demipenteract_graph_ortho.svg, so I can see how well that works when I have some time. My main annoyance is I have to upload the file to wikipedia to see how it looks! Tom Ruen (talk) 07:10, 3 February 2010 (UTC)

Geihid
Geihid's vertex figure is wrong. It should be 3.10/3.3/2.10/3. 4 T C 04:17, 1 February 2010 (UTC)


 * The notation is ambiguous when a vertex figure passes through the origin. 3/2 = retrograde 3. Tom Ruen (talk) 04:19, 1 February 2010 (UTC)


 * See Wythoff_symbol for deriving a vertex figure from the Wythoff symbol, well helps somewhat! Tom Ruen (talk) 04:21, 1 February 2010 (UTC)


 * Hmm. But it gives nonsense for sirsid - | 3/2 3/2 5/2 would mean 3.3/2.3.3/2.3.5/2 - girsid - | 3/2 5/3 2 would mean 3.3/2.3.5/3.3 - and gidisdrid - | (3/2) 5/3 (3) 5/2 isn't in the table. 4 T C 09:30, 2 February 2010 (UTC)

Crazy snubs
I found some crazy names from the snubs at Klitzing's website and put them on User:4/Snub. 4 T C 09:02, 3 February 2010 (UTC)


 * Dizzy. I'm content to avoid all the self-intersecting polyhedra for a quite a while! Convex 8-polytopes are easier! Tom Ruen (talk) 09:05, 3 February 2010 (UTC)

Image requests
We need images for the pentagrammic trapezohedron and the pentagrammic concave trapezohedron. Thanks in advance. 4 T C 12:56, 4 February 2010 (UTC)

Duals of Pentagrammic antiprism and Pentagrammic crossed-antiprism. Stella (software) has them as duals so you can make these, right? Tom Ruen (talk) 20:19, 4 February 2010 (UTC)

Uniform polychora and polytera
I'm now listing on the nonconvex stuff at User:4/Polychora and User:4/Polytera. I think I can finish the polychora soon, but I don't think the polytera can be finished anytime soon... 4 T C 06:10, 7 February 2010 (UTC)

And a spin-off of WP:3TOPE: WP:4TOPE, with a userbox. 4 T C 06:42, 7 February 2010 (UTC)


 * OH, I don't much like the nonconvex forms, and its not defendable content for Wikipedia. The ONLY public content for the nonconvex uniform 4-polytopes is 4D Stella (software), but I've not even begun to touch the nonconvex forms, except regulars, and perhaps the quasiregulars. I admit I don't bother because 2000 4-polytopes is overwhelming, especially with the confusing names and mysterious categories. I don't like to write about things I don't understand well. I expanded (renamed) the scope of WP:4TOPE as uniform polytopes, since there's no real work on higher polytopes besides uniform ones.

radicals in TeX
Concerning this edit: You wrote:
 * $$ sqrt(2). \, $$

But one can write:
 * $$ \sqrt{2}. \, $$

The TeX code is \sqrt{2}. The curly braces enclose the whole of the expression to be under the radical. Michael Hardy (talk) 19:06, 9 February 2010 (UTC)

{p/2, p}
It seems that any "polyhedron" with Schlaefli symbol {p/2, p} is a regular star "polyhedron". Here are a few images (I got the {5/2, 5} image from one you uploaded and reuploaded...)

Just curious, what would {3/2, 3} and {4/2, 4} look like? 4 T C 11:43, 10 February 2010 (UTC)


 * There are no regular star tiling in the euclidean plane that repeat periodically. Apparently they {m/2,m}, m=7,9,11... exist in the hyperbolic plane. Kalideotile doesn't show fractional anything, so I'm confused by your graphics. Others exist with vertex figures at Uniform_tiling. Some are shown at and . I've done some limited testing with them, generation, but difficult to draw in a way that makes the overlapping faces clear. Tom Ruen (talk) 00:35, 11 February 2010 (UTC)


 * This graph of a Small stellated dodecahedron as a spherical tiling, shows the difficulty of drawing overlapping faces. I colored a single pentagram face: Tom Ruen (talk) 00:38, 11 February 2010 (UTC)
 * Small stellated dodecahedron tiling.png


 * The outer edges of the triangles form a polygon which is then stellated. It is very confusing. It seems that {3/2, 3} is just a tetrahedron. 4 T C 04:49, 14 February 2010 (UTC)

WikiProject Uniform Polytopes
Tom Ruen : Would you like to join WikiProject Uniform Polytopes? Yes!! for sure! Mateus Zica (talk) 23:37, 11 February 2010 (UTC)
 * Thanks for the advice, i will hide it. I began to work on Template_talk:Polytopes

Mateus Zica (talk) 00:01, 12 February 2010 (UTC)

nice graphics
After being inspired by File:CubeAndStel.gif, here are some graphics I made using Stella showing the regular compounds:

Now all I need to find out is how to get the small icosiicosahedron done... 4 T C 09:33, 16 February 2010 (UTC)

Odd polygon db
I've started an odd polygon db template like the polyhedron one at Template:Odd polygon db and Template:Odd polygon stat table but can't seem to get it to work. Any suggestions? 4 T C 04:58, 20 February 2010 (UTC)


 * Template macro substitution is tricky, hard to see when it doesn't work. I tried renaming names from numbers to a p-prefix, and also added closing braces, seems to work - tested at User:Tomruen/temp. Tom Ruen (talk) 06:41, 20 February 2010 (UTC)
 * p.s. I never liked the "area" in the tables, too bulky. I tested a separate template for giving the area outside the table. Edit as you like! Tom Ruen (talk)!

Nomination for deletion of Template:Polygon area
Template:Polygon area has been nominated for deletion. You are invited to comment on the discussion at the template's entry on the Templates for discussion page. Thank you. 4 T C 11:19, 20 February 2010 (UTC)

File:8-cube.svg
Hi Tomruen,

do you have a special software, to easily create graphics like File:8-cube.svg? Because I wonder, that you created it totally new, instead of simply changing the existing File:Octeract Petrie polygon.svg. For me it took quite long, to manually create it in Inkscape. So I'd like to know, if there is a much easier way. It would be nice, if a created with template could be added to all these geometry graphics, showing which software has been used. Greetings, Lipedia (talk) 21:00, 26 February 2010 (UTC)


 * Hi Lipedia! Sorry for replacing your image. I wrote a program that generates the hypercube/orthoplexes/simplexes by dimension - actually an original idea from a program was from like 1987 in BASIC! So the main trick was computing the Petrie polygon projection basis. So that took some linear algebra, projecting a sequence of n vertices to [r*cos(pi/n),r*sin(pi/n)] coordinates. What I don't know in general is how to pick the right sequence of vertices for other polytopes, like Gosset 4_21 polytope, I just took a basis User:Rocchini offered. Anyway, just some little hack programs I've worked on, not in a form to share. I've thought to write a Java version that could even run as an browser Applet.
 * Oh, usually I've been just doing screen captures for graphics, but copied Rocchini's example code for creating SVG files, just lines and circles. My recent additions computed duplicated vertices, and color them by overlap order (not a problem for 8-cube). I also need to compute overlapping edges, and remove them. Then I can have some transparency and nicer antialiasing AND reduce file sizes (vital since some polytopes can have a million edges, and many overlaps in symmetric projections). I assume there's probably fancier SVG coding, maybe even scripting? It would be more compact to create vertices and draw lines referenced by vertex indices or something. Tom Ruen (talk) 21:41, 26 February 2010 (UTC)

Ah, so you know something about a special kind of graph, like Petrie polygon graphs, and use a special program for that. I thought, there may be a program, where you enter the n dimensional coordinates of whatever object, and then enter some projection parameters, to see the projection and create an SVG. Such parallel projections should be linear transformations from Rn in R2, isn't it? One reason more, to do some linear algebra ... :) Lipedia (talk) 21:29, 27 February 2010 (UTC)


 * Yes. orthogonal projections are easy. It's just dot products to me. You have two (orthonormal basis) vectors basis1 for x direction in the view, and basis2 for the y direction. You only need more basis vectors if you want to rotate the view. Tom Ruen (talk) 22:06, 27 February 2010 (UTC)

A request
Tom,

I was looking to generate the orthographic hypercube projections with my data. While I've seen the code to generate (view1,view2), it would be nice to see the generated projection vectors for each cube - can you share them (here or mailto:jgmoxness@theoryofeverything.org)Jgmoxness (talk) 00:34, 28 February 2010 (UTC)

Here's my code for computing the basis. It assumes a vertex order, effectively defining a stair-step sequence on the cube edges from one vertex to its opposite. Then I determine the basis that projects them into a semicircle. Tom Ruen (talk) 01:29, 28 February 2010 (UTC) var a:matrix_type; view1,view2,vec:vector_type; ... begin n:=cube[pickcube].dim; a.dim:=n; // pick n points (half petrie polygon path), fill as matrix v:=1; for r:=1 to n do begin for c:=1 to n do       a.a[r,c]:=cube[pickcube].vert[v].el[c]; v:=v*2; end; a.invertmatrix; // compute view1 basis vector vec.init(n); view1.init(n); for i:=1 to n do     vec.el[i]:=cos(pi*(i-1)/n); a.matrixvectormult(vec,view1); view1.scaleunit; // compute view2 basis vector view2.init(n); for i:=1 to n do     vec.el[i]:=sin(pi*(i-1)/n); a.matrixvectormult(vec,view2); view2.scaleunit; end;
 * I was refering to the 6-cube_column_graph.png type projections with code:

 begin view1.copy(dim,cube.vert[1]); view1.scaleunit; view2.init(dim); v:=1; for i:=1 to dim do begin view2.add(cube.vert[v],1); v:=v*2; end; end; view2.add(view1,-view2.dot(view1)); // force view2 perpendicular to view1 view2.scaleunit; end; 
 * I just need a few n-cube basis vector (view1,view2) pairs to get the pattern verified.Jgmoxness (talk) 01:44, 28 February 2010 (UTC)

OH! That basis was my "accidental" first attempt! Tom Ruen (talk) 02:09, 28 February 2010 (UTC)

2-cube
 * view1=(0.707106781187,0.707106781187)
 * view2=(-0.707106781187,0.707106781187)

3-cube
 * view1=(0.577350269190,0.577350269190,0.577350269190)
 * view2=(-0.707106781187,-0.000000000000,0.707106781187)

4-cube
 * view1=(0.500000000000,0.500000000000,0.500000000000,0.500000000000)
 * view2=(-0.670820393250,-0.223606797750,0.223606797750,0.670820393250)

5-cube
 * view1=(0.447213595500,0.447213595500,0.447213595500,0.447213595500,0.447213595500)
 * view2=(-0.632455532034,-0.316227766017,-0.000000000000,0.316227766017,0.632455532034)

6-cube:
 * view1=(0.408248290464,0.408248290464,0.408248290464,0.408248290464,0.408248290464,0.408248290464)
 * view2=(-0.597614304667,-0.358568582800,-0.119522860933,0.119522860933,0.358568582800,0.597614304667)

7-cube:
 * view1=(0.377964473009,0.377964473009,0.377964473009,0.377964473009,0.377964473009,0.377964473009,0.377964473009)
 * view2=(-0.566946709514,-0.377964473009,-0.188982236505,0.000000000000,0.188982236505,0.377964473009,0.566946709514)

8-cube:
 * view1=(0.353553390593,0.353553390593,0.353553390593,0.353553390593,0.353553390593,0.353553390593,0.353553390593,0.353553390593)
 * view2=(-0.540061724867,-0.385758374905,-0.231455024943,-0.077151674981,0.077151674981,0.231455024943,0.385758374905,0.540061724867)

Geometric and Math images
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Much appreciated if you could also add information to your earlier uploads :) Sfan00 IMG (talk) 17:19, 28 February 2010 (UTC)

SVG
Discussion moved to Talk:Coxeter–Dynkin_diagram, as it forms a continuation of the original discussion there. -- Cheers, Steelpillow (Talk) 19:03, 9 March 2010 (UTC)

Querco and Qrid
So you say it should be nonconvex great rhombicuboctahedron and nonconvex great rhombicosidodecahedron. I'm wondering, are there sources for these names? Can you point me to a discussion regarding this, if there is any? 4 T C 08:22, 10 March 2010 (UTC)


 * I don't remember where discussion would be, okay here at least Talk:Uniform great rhombicosidodecahedron. The origin is first Mathworld says "Uniform great rhombicuboctahedron" to distinguish from the convex truncated cuboctahedron with the same name. The wikipedia article first copied this convention, but it didn't make a lot of sense since both the convex and nonconvex forms are uniform. Norman Johnson said he support the small/great terms for the convex forms, prefers truncated naming (Truncated cuboctahedron), so now Great rhombicuboctahedron lists both, which seems good. 75.146.178.58 (talk) 02:03, 11 March 2010 (UTC)


 * Did you forget to log in? ;-) The problem is that, I'm afraid using this might be a neologism. 4 T C 08:44, 11 March 2010 (UTC)


 * Yep, no logging in. Don't worry about the name. It's just a descriptive modifier, like nonconvex uniform polyhedron. I guess it could be renamed to Great rhombicosidodecahedron (nonconvex) or something. 75.146.178.58 (talk) 22:24, 11 March 2010 (UTC)

Image uploads
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Please also use information filling out all the fields :) Sfan00 IMG (talk) 11:44, 13 March 2010 (UTC)

File copyright problem with File:Tomruen_test.svg
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check it out
hey Tom,

Just curious if you have checked out my e8Flyer.nb. If not, it would be a great time to download it and install the free Mathematica playerbecause I just enhanced the MetaFavorite selections and E8 subgroup (subplot) lists to include all but B3 (up to order 8).Jgmoxness (talk) 01:30, 14 March 2010 (UTC)


 * I tried downloading quick, got to run, but I'm not patient enough to figure it out. Sorry. Tom Ruen (talk) 08:24, 15 March 2010 (UTC)
 * hmmm.... and your patience and persistence has you tweeking wikipedia around the clock, manually coding trirectified images while ranting about the nuances of png vs. svg subcomponents of Dynkin diagrams? Sounds like there's something else in play. I would like to know since it seems a capability to visualize hyperdimensional information is badly needed in math/science. Can you elaborate? (I do provide Youtube video tutorials on theoryofeverything.org, albeit a bit dated).  BTW - getting closer to finding the 18x7 ring E7 projection basis vectors for the split real even E8 group).Jgmoxness (talk) 14:07, 15 March 2010 (UTC)
 * oh - and for a quick "no-brainer start" to using the tool, simply select from any of the ~50 "MetaFavorite" drop down menu(s) (AND & OR) in the very upper left corner of the UI. These automatically press the UI buttons/sliders to create the most common / favorite Lie Group & Polychora visualizations (including your n-cube Pascal Triangle / Hasse diagram graphs). The "refesh" button is for refreshing the graph after manually changing the UI parameters that don't "auto update". All buttons/slider functionality is described in E8 investigation tool and compared to another physics based tool from Lisi -the Elementary Particle Explorere (ECE) Jgmoxness (talk) 01:06, 16 March 2010 (UTC)

Polygon Infobox
Hello, great work on the square, cube and etc articles. I noticed that Triangle and other related articles didn't have an infobox so I slapped together a simple one for them: Template:Infobox_Polygon. It supports all the parameters I could find. Perhaps it can be used in other articles as well. --Hutcher (talk) 17:10, 4 April 2010 (UTC)


 * Hi Hutcher. I added tables for regular polygons, so there's one under equilateral triangle. Triangle is less useful since many types, and Schläfli symbols, Coxeter–Dynkin diagrams, Symmetry group, Area, Internal angle, and properties are not defined, or not simply defined in general triangles. Even for the regulars the main reason I didn't make an infobox for the regular polygons is I still didn't clearly know what should be included. In fact I'm thinking right now that a "family" field could be added, with an equilateral triangle as a 2-simplex, and a square as a 2-hypercube, and an 2-orthoplex. Tom Ruen (talk) 21:33, 4 April 2010 (UTC)

demi hypercubes and Coxeter Dn
On the demihypercube page in Aug 2008 you added a reference to Coxeter Dn groups being related to the demihypercubes (where the Cn groups are the n-cubes. Can you help me with references to where this is defined? (only thing on the net references that wiki page)Jgmoxness (talk) 00:30, 12 April 2010 (UTC)


 * Conway lists the Coxeter-Dynkin diagrams for the hemicubes, these being the graphical versions of the Dn Coxeter groups. The Dn groups are the only reflective symmetry that generates the n-demicubes, although they can also be generated by an Alternation (geometry) operation from the Bn group, which effectively removes a mirror, doubling the fundamental domain. I'm not sure what more you're looking for. See also Coxeter_group. Tom Ruen (talk) 20:41, 12 April 2010 (UTC)
 * John H. Conway, Heidi Burgiel, Chaim Goodman-Strass, The Symmetries of Things 2008, ISBN 978-1-56881-220-5 (Chapter 26. pp. 409: Hemicubes: 1n1)
 * Yes, thanks. I am trying to correlate it with the Simple Lie group article that Dr corresponds to the special orthogonal group, SO(2r).
 * The SO(2r) root systems are generated with (+/-1, +/-1,0,0,....) patterns, as in SO(8),SO(10), and part of the E6 (mathematics). It seems that this pattern is different than the demicube pattern of (+/-1, +/-1,...) with odd number of + signs. Am I wrong in trying to associate the Coxeter Dn and Lie Dn=SO(2n)?Jgmoxness (talk) 02:10, 13 April 2010 (UTC)
 * Oh, my! I only know something of the geometry side, doesn't sound right to me, wouldn't put any simply correspondence between coordinates and groups, but I'm not in a good place to judge. (I mean for instance I saw that 4_21 polytope has the vertices matching the rectified 8-orthoplex, and 8-demicube, but does that mean a relationship between E8, D8, no idea!) Tom Ruen (talk) 02:31, 13 April 2010 (UTC)

Crossed Rectangles
Please see my comments at File talk:Crossed rectangles.png and at Talk:rectangle. Just one day after the image file was created, someone has used "crossed-rectangle" in such a way that resulted in his altering the very definition of rectangle without sourcing. I am suggesting we find another name for the image file to reduce the likelihood of a recurrence -- or that someone find a source for any of this. --JimWae (talk) 19:22, 23 April 2010 (UTC)

File:10-cube.png listed for deletion
A file that you uploaded or altered, File:10-cube.png, has been listed at Files for deletion. Please see the to see why this is (you may have to search for the title of the image to find its entry), if you are interested in it not being deleted. IngerAlHaosului (talk) 16:01, 25 April 2010 (UTC)

hemi verfs
You may wonder why I'm changing your recent insertion "It has a crossed-quadrilateral vertex figure" to "Its vertex figure is a crossed quadrilateral" wherever I see it:

Mainly because, with your version, a naive reader could infer that the important part of the sentence is "It has a vertex figure." —Tamfang (talk) 04:07, 2 May 2010 (UTC)

I missed that, but looks good! Thanks! :) Tom Ruen (talk) 20:41, 15 June 2010 (UTC)

File:Tomruen test.svg missing description details
Dear uploader: The media file you uploaded as File:Tomruen test.svg is missing a description and/or other details on its image description page. If possible, please add this information. This will help other editors to make better use of the image, and it will be more informative for readers.

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 * It's just upload name I use when I'm testing SVG files, since I can't test them without uploading. Tom Ruen (talk) 06:27, 3 May 2010 (UTC)

File:Example polytope graph TLR.png
Thank you for uploading this media, (it's appreciated.)

However, it would be nice if you could give some kind of indication as to what license the media is under. That way other people can be confident in making use of it for many varied purposes :)

Adding license information also helps prevent media you've put effort into creating from being deleted :)

You may wish to read Image_copyright_tags which will assist you :)

The image should probably be SVG anyway. Sfan00 IMG (talk) 18:05, 18 May 2010 (UTC)


 * The image was for demonstration purposes, discussion for a "common layout" of polytope graphs. It's not intended for article usage. I fixed the licensing as PD - it was missing a closing brace. Tom Ruen (talk)

Bucklin
You may be interested to know that there is a dispute about the Bucklin voting page ongoing. The issues are:


 * 1) Can the term "Bucklin voting" comprehend systems which allow equal and/or skipped rankings?
 * 2) If so, do such systems meet the IIA and Clone independence criteria?

(One possible answer to either question is that we can't say either way because we don't have relevant citations to reliable sources. In that case, we must choose what we can say.)

Your participation in the discussion might help us attain consensus.

Cheers, Homunq (talk) 01:37, 20 May 2010 (UTC)


 * Bucklin absolutely doesn't support equal rankings, since the purpose of Bucklin is to treat all ballots equally, so the first round everyone gets one vote, second round 2 votes, etc. Any other interpretation would be something different. Any other interpretation denies the basis of voters to support a multiple vote option as "fair". But I don't have sources, or motive to be in an argument. I assume the issue comes out with Approval/Range voting advocates who are forever trying to make a case for multiple votes, and I've never found any resolution/compromise against their agenda. Tom Ruen (talk) 05:06, 20 May 2010 (UTC)

The place for this debate is on Talk:Bucklin voting, where Markus Schulze has already reposted your comment. Homunq (talk) 17:24, 20 May 2010 (UTC)

3^pqr (Gosset-Elte_figures)
Is there an article for [3p,q,r] polytopes in general? Ought there to be one?

The question is prompted by my doodling last night to find which of them are flat: 521, 331, 222, 1111. —Tamfang (talk) 17:05, 9 June 2010 (UTC)

Here's an ugly draft survey: User:Tomruen/Gosset-Elte_figures Tom Ruen (talk) 17:54, 9 June 2010 (UTC)

Someone told me the name and definition, a google search finds. Tom Ruen (talk) 17:59, 9 June 2010 (UTC)

POTD notification
Hi Tom,

Just to let you know that the Featured Picture File:Lunar_libration_with_phase_Oct_2007.gif is due to make an appearance as Picture of the Day on June 18, 2010. If you get a chance, you can check and improve the caption at Template:POTD/2010-06-18.  howcheng  {chat} 19:04, 14 June 2010 (UTC)


 * Cool! The caption looks good, but the animation isn't working - something with the wiki-display of rescaled gifs. I don't know what can be done. I could upload a smaller copy. Tom Ruen (talk) 19:33, 14 June 2010 (UTC)
 * Oh, someone already made a scaled-down version: Lunar libration with phase Oct 2007 (continuous loop).gif Tom Ruen (talk) 19:35, 14 June 2010 (UTC)

You are now a Reviewer
Hello. Your account has been granted the "reviewer" userright, allowing you to review other users' edits on certain flagged pages. Pending changes, also known as flagged protection, will be commencing a two-month trial at approximately 23:00, 2010 June 15 (UTC).

Reviewers can review edits made by users who are not autoconfirmed to articles placed under flagged protection. Flagged protection is applied to only a small number of articles, similarly to how semi-protection is applied but in a more controlled way for the trial.

When reviewing, edits should be accepted if they are not obvious vandalism or BLP violations, and not clearly problematic in light of the reason given for protection (see Reviewing process). More detailed documentation and guidelines can be found here.

If you do not want this userright, you may ask any administrator to remove it for you at any time. Courcelles (talk) 20:38, 15 June 2010 (UTC)

Commons image
You updated File:24-cell graph.svg earlier this month, but its May 2010 transfer to Commons did not include that update. I verified the bot move there (see ) but did not delete the local file, as you may prefer to update the Commons file first. – Athaenara ✉  09:33, 22 June 2010 (UTC)

File copyright problem with File:6-orthoplex.svg
Thank you for uploading File:6-orthoplex.svg. However, it currently is missing information on its copyright status. Wikipedia takes copyright very seriously. It may be deleted soon, unless we can determine the license and the source of the file. If you know this information, then you can add a copyright tag to the image description page.

If you have uploaded other files, consider checking that you have specified their license and tagged them, too. You can find a list of files you have created in [ your upload log].

If you have any questions, please feel free to ask them at the media copyright questions page. Thanks again for your cooperation. IngerAlHaosului (talk) 17:17, 2 July 2010 (UTC)

Nomination for deletion of Template:Great Stella
Template:Great Stella has been nominated for deletion. You are invited to comment on the discussion at the template's entry on the Templates for discussion page. Thank you. WOSlinker (talk) 09:38, 17 July 2010 (UTC)

Nomination for deletion of Template:Stella4D
Template:Stella4D has been nominated for deletion. You are invited to comment on the discussion at the template's entry on the Templates for discussion page. Thank you. WOSlinker (talk) 09:39, 17 July 2010 (UTC)

Abstract polytopes
You have previously contributed to the Abstract polytope article. If you feel able, please contribute to the discussion on Notation, where I am hoping to resolve a long-standing dispute. Many thanks in anticipation. &mdash; Cheers, Steelpillow (Talk) 14:44, 17 July 2010 (UTC)

polyhedron
Hi Tomruen, just to explain, I made the modification for the dodecahedron because it was previously marked as needing conversion to SVG. I see that this tag is no longer present on the image, so I won't bother changing the rest. gringer (talk) 22:55, 28 July 2010 (UTC)

language in polytope lists

 * There are 271 forms based on all permutations of the Coxeter-Dynkin diagrams with one or more rings. (256+16-1=271 cases) Nine cases are enumerated below, five single-ring: Five rectified forms, three 2-ring truncations, and the final omnitruncated form. Bowers-style acronym names are given in parentheses for cross-referencing.

I dislike the word enumerated here: it normally means a complete list, or at least an attempt to count how many solutions exist, which you did in the preceding sentence. That's why I've been changing it to shown.

Watch out for syntax or punctuation that (as here) includes the two-ring forms among the single-ring forms.

Cross-referencing with what? —Tamfang (talk) 17:06, 29 July 2010 (UTC)


 * Agreed enumerated replacement is good. Klitzing uses BSA, so that's my defense in including them, since his lists are the only online references. Tom Ruen (talk) 18:29, 29 July 2010 (UTC)

n-demicube families
For [3,..,31,1], why not say something like:
 * N of these are listed above: those in whose symbols the two 'tail' nodes are both marked or both unmarked.

As they stand now, these sections look rather random. —Tamfang (talk) 07:58, 10 August 2010 (UTC)


 * That sounds good. Feel free to reword, and thanks for all your kind cleanup efforts. :) Tom Ruen (talk) 19:50, 14 August 2010 (UTC)

Cygnus is misspelled in your map.
http://en.wikipedia.org/wiki/File:Summer_triangle_map.png Cygnus is misspelled in your map. Regards Steve Lord lord@ipac.caltech.edu —Preceding unsigned comment added by 134.4.20.206 (talk) 21:59, 12 August 2010 (UTC)


 * I fixed it! Tom Ruen (talk) 19:46, 14 August 2010 (UTC)

231 polytope
I wonder if you know what the vertex coordinates of the 231 polytope are. Article mentions that Elte has named it V126 (this is also mentioned in Coxeter's book "Regular polytopes", p.210). I looked up Elte's thesis (p.118.) and it seems to me that the vertices of 231 are essentially the same as those of E7. Is that the case? Also, I was trying to reconstruct it from its Coxeter-Dynkin diagram, but I couldn't understand what the ring on the first vertex means. --Marozols (talk) 22:56, 13 August 2010 (UTC)


 * I replied at Talk:2_31_polytope. Tom Ruen (talk) 19:47, 14 August 2010 (UTC)

Great work !
Amazing... Jgmoxness (talk) 01:20, 14 August 2010 (UTC)


 * Thanks! I computed the edges too, but the SVG file was too large to be drawn. (limited ~5 meg?) Tom Ruen (talk) 19:39, 14 August 2010 (UTC)

Talk:Archimedean solid
Hi, could you upload the six Archimedean solids in question with yellow and blue exchanged? I don't understand why you chose these colors instead of these  for the new files. Greetings, Lipedia (talk) 22:29, 18 August 2010 (UTC)


 * The first set were generated by Stella (software) and it picked the colors automatically. The second set were generated by KaleidoTile, and it has a consistent color by position within the Fundamental triangle between different truncations. Stella might allow manual overrides, not sure, but too many images for me to want to do that. (And the stella images are also annoying, shaded coloring that varies slightly so I can't easily use MSPaint to replace faces with colors!) Tom Ruen (talk) 01:18, 19 August 2010 (UTC)

I see that I can exchange the colors with GIMP. The shaded coloring is no problem. E.g. 585800 has to be replaced by 000058, etc. It's rather a problem, that some pixels around the new color still have the old. But one has to look carefully, to see the them. If you have no objections, I'm going to overwrite the old files on Commons. Lipedia (talk) 12:12, 19 August 2010 (UTC)


 * Right, since the stella image generation used "oversampling", there's color blending on the transition colors that might be visible in the changes, but change as you like and we can see. Tom Ruen (talk) 18:52, 19 August 2010 (UTC)

Hello
Hello from New Zealand —Preceding unsigned comment added by Prabhaats (talk • contribs) 06:29, 24 August 2010 (UTC)

{{#ifeq:{{{header}}}|2|

Nomination for deletion of Template:Stella4D
}} Template:Stella4D has been nominated for deletion. You are invited to comment on the discussion at the template's entry on the Templates for discussion page. Thank you.. The result from the previous discussion was a bit unclear. So I'm re-listing it to gain consensus.Salix (talk): 14:57, 30 August 2010 (UTC)

en:Talk:Coxeter-Dynkin diagram symbols
I reloaded File:CDW 20.svg (and 10,17) which is a duplicate of "File:CDV 20.svg" BUT the W name is the correct one, to be consistent with all the other symbols. I created the symbol system for building up Coxeter-Dynkin diagrams. The SVG author named it "V" as a temporary parallel set, but "W" means ("Whole"), while "V" means nothing at all. Tomruen ( talk ) 00:11, 30 August 2010 (UTC)
 * OK :). But as someone said on your Commons talk page, don't load duplicates for experiments in renaming or such :) Cheers. notafish }&lt;&#39;;&gt; 07:08, 4 September 2010 (UTC)

Final warning
Your blatant re-insertion of missing images to templates is disruptive. If you upload more images add them. Do NOT blindly revert, rather just add back the images you uploaded. You where told by myself and another that that action was not appropriate. If you continue your disruptive behavior further action may be sought, which may include but is not limited to blocking. ΔT The only constant 00:43, 14 September 2010 (UTC)


 * How is it disruptive? I'm the only one editting. The images are in process, generated but not uploaded. Why should I waste my time with copy&pasting partial updates when your cleanup operation is automated? What's the real problem here? Tom Ruen (talk) 00:47, 14 September 2010 (UTC)
 * There is a simple solution, either update the template as needed when you upload more content, or wait until everything is uploaded before adding it to the template. What your doing right now is introducing garbage into 7 articles, which makes them look horrid. I am not an automated program so please dont assume my actions are, I just happen to be good at what I do. ΔT The only constant 01:05, 14 September 2010 (UTC)

You both are clearly edit warring over this, and hence I have full-protected the template for 12 hours (note that does not mean that I support any one's version). I suggest you both work it out yourselves either here or on the template's talk page. Regards, –MuZemike 01:01, 14 September 2010 (UTC)

Mr DeltaT has performed two contradictory operations (1) Removing links that are in process to be loaded (2) Minor cleanup operations that have no actual functionality, but apparently are better. These operations are contradictory because the first one MUST be reverted to avoid retyping, and reverting loses the second minor effect which makes Mr. DeltaT swear. So he's the source of the conflict, and the there's no other solution but reverting his cleanup work, either when I'm done or partially done. Tom Ruen (talk) 01:12, 14 September 2010 (UTC)
 * My issues are not with reverting the minor code cleanup that I did in the table, but rather your introduction of 80+ missing images. Either dont create the template until all images are uploaded, add them to the template as you upload them (something you seem not to be able to do), or wait until everything is uploaded before reverting. ΔT The only constant 01:15, 14 September 2010 (UTC)


 * Why are temporary open image links so offensive when open article links fine? It is much easier to see my progress when the blank images are there. I don't see the harm in wanting to be lazy and leave a few blank images in process. Tom Ruen (talk) 01:20, 14 September 2010 (UTC)
 * If it was just one or two images on a single article this wouldn't be as big of a deal, but right now your displaying a total of 576 broken images across 7 articles. Im not sure how that could be acceptable. The fact that your doing this because your lazy just makes it all the worst. When templates puke broken images it lowers the quality of what we do here. ΔT The only constant 01:27, 14 September 2010 (UTC)


 * Nah, it shows Wikipedia is a project in motion! People love to see skyscrapers and bridges half-done, gets 'em excited and knowing more is coming. Tom Ruen (talk) 02:11, 14 September 2010 (UTC)
 * p.s. How about giving me a batch-upload option, and everyone can be happy! Tom Ruen (talk) 02:14, 14 September 2010 (UTC)
 * commons:Commons:Tools might be what your looking for. ΔT The only constant 02:24, 14 September 2010 (UTC)


 * That was useful - thanks! They're all uploaded now, User:Tomruen/Enneazetton_family, although rendering failing on highest few. Tom Ruen (talk) 04:17, 14 September 2010 (UTC)

File:Twelfth stellation of icosidodecahedron.png missing description details
Dear uploader: The media file you uploaded as File:Twelfth stellation of icosidodecahedron.png is missing a description and/or other details on its image description page. If possible, please add this information. This will help other editors to make better use of the image, and it will be more informative for readers.

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File:Thirteenth stellation of icosidodecahedron.png missing description details
Dear uploader: The media file you uploaded as File:Thirteenth stellation of icosidodecahedron.png is missing a description and/or other details on its image description page. If possible, please add this information. This will help other editors to make better use of the image, and it will be more informative for readers.

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File:SoE2002Dec04T.gif
Good afternoon,

I'm writing to you to confirm the file have successfully been renamed and could now be used in relevant templates.

Best Regards, --Dereckson (talk) 15:19, 25 September 2010 (UTC)


 * Uh oh! It SHOULD be File:SE2002Dec04T.gif, no o! Tom Ruen (talk) 01:19, 26 September 2010 (UTC)

STV
Hi, now that you've redirected STV to a disambiguation page, we've been left with a bit of a mess - over 500 links that now go to a disambiguation page. Those links need to be manually redirected; I've taken care of 150 or so. Per WP:FIXDABLINKS, could you help with the leftovers? Navigation popups with the popupFixDabs flag set to true is very helpful. If you could fix all of the links that should not point to STV Television, and let me know, I could do a mass edit to fix the remainder. Thanks, -- Ja Ga  talk 11:18, 26 September 2010 (UTC)


 * Wow, that's a lot of links. Thanks for noting the disconnect I caused. None seemed to be the Election method meaning, so I assume all relate to the TV, and a mass-edit would seem appropriate. The only question for me perhaps if STV Television is the best name. It would be good if that can be confirmed before renaming all the links! Tom Ruen (talk) 13:22, 26 September 2010 (UTC)
 * Hmm, if every single link is in the STV Television link sense, we should let STV redirect to STV Television as the WP:PRIMARYTOPIC and put a redirect template on STV Television for the disambig. -- Ja Ga  talk 20:03, 26 September 2010 (UTC)
 * Not every single link. So far, I've found one for an Estonian company, one for a Slovenian, one for a Taiwanese (with no Wikipedia article), and two for the voting system.  Still, I think this is one of those situations where declaring a primary topic is tricky, because what's most likely for a Scottish user to search isn't necessarily what's most likely for a user from elsewhere.  --R'n'B (call me Russ) 16:01, 28 September 2010 (UTC)
 * Yeah, I was thinking that too - that's why I didn't go ahead and change it to STV Television. -- Ja Ga  talk 09:25, 29 September 2010 (UTC)

Bowerism

 * Great rhombated pentachoron (Acronym: grip) (Jonathan Bowers)

(etc.) I wouldn't capitalize acronym. What do you think of these forms?


 * Great rhombated pentachoron ("grip") (Jonathan Bowers)
 * Great rhombated pentachoron, or grip (Jonathan Bowers)

—Tamfang (talk) 02:27, 27 September 2010 (UTC)


 * I'm ok with any of the 3. I agree it would be good to be consistent in style between articles. I'm also testing a database, and stat table, like at Rectified 6-simplex. Tom Ruen (talk) 03:23, 27 September 2010 (UTC)

Meetup
Hello, Tom. Discussion of a 2010 Minnesota Wikipedia Meetup has begun. Please see the talk page. Jonathunder (talk) 23:20, 27 September 2010 (UTC)

Interesting images and research
Your imaging work is pretty impressive and it makes me think of the climate work I'm trying to finish. I punched new holes into my globe so that the North pole is at 30°N & 173°E, near the center of the North Pacific. That makes for a lot of climate changes and extra temperate land. It's been tricky doing a flat map image that I can paint and do conversions with. I intend to do both a climate zone experiment and later a gaming mod map.

Do you have any imaging suggestions?? GabrielVelasquez (talk) 01:46, 3 October 2010 (UTC)

The image I just added was (digital) hand painted.GabrielVelasquez (talk) 01:51, 3 October 2010 (UTC)


 * Interesting. I have a program I wrote (similar to Celestia) that takes maps flat maps (like ) onto a solar system simulator, so I've made images, and animaions like File:Saturn_view_from_earth_2009.gif and File:Saturn_timelapse-29_years.gif and File:Lunar_eclipse_chart_close-2010Dec21_animation.gif for Wikipedia but haven't done much with actually making or editing my own source maps. So I don't have any suggestions really for the creative side. Have fun with your creations! Tom Ruen (talk) 02:01, 3 October 2010 (UTC)

Re: Gliese 581 g
I removed the internal link you added to the lead section under "unconfirmed". That's generally unnecessary. Links in lead sections are used sparingly for key concepts. Viriditas (talk) 11:19, 13 October 2010 (UTC)


 * Ok. Its still better now with the subsection added to discovery. Tom Ruen (talk) 11:24, 13 October 2010 (UTC)
 * I'm just curious, where did you get the idea from? Do you know of any FA or GA articles that use internal links in the lead section?  I ask because I'm not aware of any, but would welcome a correction on this.  I do recall it being a popular style in 2004-2005, but I think it has fallen out of favor, as I rarely see it used, if at all. Viriditas (talk) 11:36, 13 October 2010 (UTC)


 * I use article#section w-linking quite a lot, and I've tried a bit with #section linking from the intro into an article section, but I admit it is inferior/confusing compared to a TOC, since you normally expect links to go to other articles. (Plus it gets disconnected if anyone renames a section header) So I accept good section/subsection titles are best navigation! Tom Ruen (talk) 11:58, 13 October 2010 (UTC)
 * Interesting. Are there two schools of thought on the subject? Viriditas (talk) 02:10, 14 October 2010 (UTC)


 * Ummmm... I was just trying to agree with you that anchor linking isn't best. :) Anchor linking between articles is also problematic since section titles can be changed without any way of knowing something has been linked to it. Tom Ruen (talk) 22:40, 14 October 2010 (UTC)

E7 Coxeter and more
Tom,

Today I was given a URL by User:Natmaka which referenced work by Madore.

After a short email exchange, Madore calculated for me the 18-gon E7 basis vectors.

Projection18
 * H = {-0.355630637789279`, -0.108612189090733`, -0.0526176526745836`, 0.819873464669292`, -0.355630637789279`, 0.2138474944399`, -0.108612189090733`, -0.0526176526745837`};
 * V = {0.505682626201259`, 0.298409537004325`, -0.0191512593705059`, 0.298409537004325`, 0.0911364478073912`, 0.298409537004325`, 0.298409537004325`, 0.615970333379156`};

I know with these, you will now be able to go crazy with your polytope symmetries. BTW - he also has the 20 and 24-gon symmetries.

Projection20
 * H = {0.594095480117793, 0.392376873691752, 0.193033322933216, 0.107623126308248, 0.0940954801177932, -0.455898878992783, -0.416640120683195, -0.232292081242804};
 * V = {-0.0940954801177932, 0.455898878992783, 0.416640120683195,0.232292081242804, 0.594095480117793, 0.392376873691752,  0.193033322933216, 0.107623126308248};

Projection24
 * H = {0.622590719424075, 0.197882519146208, 0.382279671628927, -0.0424285286489395, -0.0819656231869130, -0.257885519793075, -0.498196567588223, -0.322276670982061};
 * V = {0.0819656231869130, 0.257885519793074, 0.498196567588222, 0.322276670982061, 0.622590719424075, 0.197882519146208,  0.382279671628927, -0.0424285286489402};

greg Jgmoxness (talk) 01:30, 18 October 2010 (UTC)


 * Looks fun - thanks! I'll try some graphs. I don't know what to call the 20/24 symmetry projections, but they're listed under Coxeter_number (E8 Degrees of fundamental invariants=2, 8, 12, 14, 18, 20, 24, 30). Tom Ruen (talk) 05:52, 18 October 2010 (UTC)

The E7 plane worked, but the 20/24 vectors were not symmetrical. Tom Ruen (talk) 22:52, 18 October 2010 (UTC)

Amazing DUDE! Beautiful! I think you have the material for wonderful full color "coffee table" book with your visualizations.

I might suggest (per Madore and convention) that you credit the original sources of the group projection vectors your using (e.g. at least the E6 12 and E8 30-gon I gave you last year and now the the E7 18-gon that Madore supplied this week).Jgmoxness (talk) 02:47, 20 October 2010 (UTC)


 * There's a lot I should do with credits/documentating. I'd rather credit sources by links than just give blind numbers, especially since reused in many images. I do see SVG files allow comments, so that's an option too, since files are autogenerated. Most lacking now is the vertex colors ought to be documented by multiplicity counts, as comments at least, or better as "caption" information within the images.


 * I also updated the E7 family polytope graphs. The tricky part is its all in 8D, while polytopes in 7D, so I had to manually select "vertex figures" from 4_21 to find a symmetric 3_21 graph in the E7/18-gonal symmetry vectors given. SO for the 7D figures, you'd need to give BOTH the coordinate basis AND projection vectors to be meaningful. Tom Ruen (talk) 02:48, 21 October 2010 (UTC)


 * In the interest of knowledge sharing, I prefer disclosing more information (like specific projections), but I just put a credits reference to the source of the projection vectors in the file description text in wiki commons.


 * Not sure why you didn't get 20 & 24-gon symmetries. See my rectified versions....


 * I'm not sure what these pictures ARE (what polytope?!). I see 4-fold symmetry above, not 20 or 24. Tom Ruen (talk) 05:08, 21 October 2010 (UTC)


 * It is more obvious in the unrectified pics w/o overlapping vertices.Jgmoxness (talk) 13:40, 21 October 2010 (UTC)


 * Thanks. I got mine working too, did my copy&paste too quick! Also I see by "rectied" you mean "rectified 4_21", points on mid-edges of 4_21 polytope. Tom Ruen (talk) 22:43, 21 October 2010 (UTC)


 * I've automated the vertex selection process from E8 to E7 by using the fact that they are orthogonal (that is, select only the vertices with 2 dimensions that are the same).
 * Jgmoxness (talk) 04:20, 21 October 2010 (UTC)

File:Moon-crater-Plato-nov10-2005.png
I really like this photo and was going to add the move-to-commons tag, so that all the Wikipedia medias can use it. However, I have a minor concern. I'm afraid that the copyright nuts are going to say that you couldn't have taken this image. So I was wondering if adding "Photo of Moon and crater Plato. Taken by Tomruen using Telescopic photography" would be an accrete statement. That way it is clear that you too the image yourself and didn’t' get it from NASA or some other source. I'm not 100% sure myself how you say you got this image, so I don't what to change the information without making sure it's accurate.


 * Sure, done! It is amazing what a digital camera can do with a 30 year old telescope I've had since I was a kid! Tom Ruen (talk) 19:14, 19 October 2010 (UTC)
 * I am very impressed. Like I said I wanted to make sure that the copyright nuts don't say "He didn't take that photo himself".


 * Thanks! It looks like there's a better one on the german wiki Tom Ruen (talk) 19:21, 19 October 2010 (UTC)
 * I'm not sure if it's better per say, but it still should be in commons for use anyway.--ARTEST4ECHO (talk 19:26, 19 October 2010 (UTC)


 * Someday maybe Wikipedia will get some REAL professional crater images, like, often just a matter of emailing the photographer for permission, but takes time! Tom Ruen (talk) 00:09, 20 October 2010 (UTC)

The JWST
The planned orbit of the JWST is so counterintuitive that this article would have been screwed up forever had you not pointed out the correct orbit. Thanks. Hopefully we'll get a diagram of the thing into the article somewhere, since it's difficult to describe in words. S B Harris 02:34, 20 October 2010 (UTC)


 * It is confusing, unsure if I helped. After I figured it out, I thought about copying the NASA diagram, but happy for now to learn about halo orbits. I'll have to get out my gravity simulator someday and try it! Tom Ruen (talk) 02:47, 20 October 2010 (UTC)

Eclipse
Hope you don't mind about me hacking the eclipse article about. I used to think that we ought to use templates more but I'm not sure our editors can cope. HOWEVER I'm really intrigued by these root pictures. Is there a communicator who can reduce this back to basic maths knowledge? I'm intrigued. Victuallers (talk) 21:09, 21 October 2010 (UTC)


 * Hi Victuallers. I was glad for your help on the historical eclipse. I set up a lot of solar eclipse article stubs hoping it would encourage others to expand them. I did some quick google searches on some and added link information on expeditions. The templates can do tricky things, but hopefully understandable once they are set up. Tom Ruen (talk) 22:36, 21 October 2010 (UTC)
 * p.s. On "root pictures", the symmetric graphs above? The hypercube article might help with some understanding, viewing higher dimensional polytopes as 2D projections. Tom Ruen (talk) 22:44, 21 October 2010 (UTC)

Uniform polyzetton
Hey, it is now the second-longest article in Wikipedia (Special:LongPages). Please move some of the tables to a separate article to reduce the size. Also please consider adding some plain language description so that non-math people could understand what this is all about. Thanks for your work. Renata (talk) 16:04, 29 October 2010 (UTC)


 * Thanks, its in progress. Definitely needs to be split, more on the number of pictures and download time, and I have some ideas how to do it. Tom Ruen (talk) 18:12, 29 October 2010 (UTC)

Even permutohedron
Hi TomRuen,

Remember the n-permutohedron that was proven to be the omnitruncated (n-1)-simplex? I stumbled upon this paper today that studies the even permutohedron (i.e., the convex hull of all even permutations of the vertices):



Now I'm curious as to whether it corresponds with any of the known uniform polytopes. Any ideas?&mdash;Tetracube (talk) 00:14, 11 November 2010 (UTC)


 * Interesting. What are the lower forms? So n=2 creats a triangle, instead of hexagon. I'd guess it's an Alternated omnitruncated n-simplex, or snub n-simplex since! (2:triangle (snub hexagon), 3=icosahedron (snub tetrahedron), 4=snub 5-simplex, ...), but not uniform above n=4. And the icosahedron will only be topological, not regular, without the golden ratios. Tom Ruen (talk) 01:26, 11 November 2010 (UTC)

p.s. are these your coordinates from snub 24-cell?

Another possible similar series?! (using all orthants, and above series are facets from these)


 * Actually, the coordinates I used for rendering the snub 24-cell projection images are derived from Coxeter's 600-cell coordinates by subtracting the vertices of an inscribed 24-cell. It turns out that I subtracted the vertices of a different 24-cell than the one that yields the coordinates you give above, so no, I don't have the same coordinates. :-) I have not tried to derive them directly from the Coxeter-Dynkin diagram. But I believe the coordinates listed on Snub 24-cell are from Coxeter's Regular Polytopes. It is how he got the coordinates for the 600-cell in the first place. (As an interesting aside, he alludes to a different set of coordinates for the 120-cell, derived by an earlier researcher, which aren't as "nice" as the ones he gives in the book; I don't know if I dare to look at them. :-P)&mdash;Tetracube (talk) 00:43, 18 November 2010 (UTC)

File:Digonal dihedron.png missing description details
Dear uploader: The media file you uploaded as File:Digonal dihedron.png is missing a description and/or other details on its image description page. If possible, please add this information. This will help other editors to make better use of the image, and it will be more informative for readers.

If the information is not provided, the image may eventually be proposed for deletion, a situation which is not desirable, and which can easily be avoided.

If you have any questions please see Help:Image page. Thank you. Sfan00 IMG (talk) 12:53, 13 November 2010 (UTC)

Commons talkpage
poke Krinkle (talk) 01:38, 16 November 2010 (UTC)

HELP Compressed SVG?
helpme

I've been uploading SVG graphic files, some rather large (like File:2_41_t0_E8.svg). I noticed that the SVG format supports compression, with a *.svgz extension, but Wikipedia (commons) upload doesn't recognize it. Is there a way to do this NOW, or are there plans to support this? Tom Ruen (talk) 06:20, 16 November 2010 (UTC)

According to SVG image support: "A patch to enable SVGZ (GZipped SVG) images is available. Support has not yet been integrated into the official MediaWiki distribution." If you want to know more, you could ask over there. Bovlb (talk) 08:20, 16 November 2010 (UTC)


 * Thanks for the link! Tom Ruen (talk) 05:53, 17 November 2010 (UTC)

Deriving coordinates from Coxeter-Dynkin diagrams
After you asked about coordinates for the demihypercubes, I've been thinking about how to derive coordinates from Coxeter-Dynkin diagrams. The key ingredient in my scheme for reading the CD diagrams for the hypercube truncates is the "all permutations of coordinates, all changes of sign" operation (abbrev. APACS) performed on the base point. The APACS operation is essentially equivalent to reflecting the base point across all the symmetries of the hypercube; it just so happens that it maps very nicely to the Cartesian coordinate system, which is convenient for us. And it also happens that the n-hypercubes have an obvious relation with the (n&minus;1)-simplices, so we also get a nice representation of coordinates for the simplices.

Of course, the uglier side of things show up a little bit when we transform the (n+1)-dimensional coordinates of the simplicial truncates back into n-space; on that relevant userpage of mine, I have derived a matrix that performs this transformation in what is possibly the nicest way. (It gives the coordinates for the n-simplices in an interesting pattern that is related to the square numbers and triangular numbers.) But still, you see that the coordinates do get a little out-of-hand when you get to the more complex truncates.

Now, we don't have to start from the hypercubes to get the coordinates; we can, for example, derive the n-simplex by starting with a point displaced from the origin, which we then reflect across the simplex's symmetries to generate the other points. If the point lies on one of the lines of the simplex's axial symmetries, then a simplex is generated; by moving this point off the axis carefully, we can generate the various n-simplex truncates. (Indeed, this is the underlying thought in the CD diagrams.) Using the same principle, we could generate the icosahedral and 600-cell truncates; but coordinates derived this way would hardly be manageable except by a machine. Just as the coordinates for the tetrahedron as the alternated cube are much nicer than the coordinates derived by mapping (n+1)-dimensional coordinates back to n-space, so the coordinates Coxeter (and those before him) derived by exploiting the special connection between the 600-cell and the 24-cell are much nicer than any "brute-force" method of computing directly from the CD diagrams.

All hope is not lost, however. It may be possible to perturb the coordinates of the 24-cell in such a way that when we "snub" it, we get a "pseudo-truncate" of the snub 24-cell, which we can then stellate using analogously truncated icosahedral pyramids. This may yield nicer coordinates than the brute-force method; although I suspect that at this point we might as well just generate the truncates programmatically instead.

As for the hemihypercubes that you asked about, if I'm not mistaken you can get its coordinates by using an APECS operation instead (all permutations of coordinate, even changes of sign). It may be possible to derive hemihypercube truncates from base points by using APECS instead of APACS. Something I'll have to think about.&mdash;Tetracube (talk) 01:14, 18 November 2010 (UTC)


 * Thanks for your thoughts Tetracube. Now that I'm comfortable with Coxeter plane projections, I'm looking at other dimensional drops, and find there's something called "Geometric folding", doubling up nodes in a Coxeter-Dynkin diagram, and lowering the dimension. So I'm thinking the mapping of Dn --> B(n-1) is helpful. It means basically a Dn polytope has B(n-1) symmetry, so if you "drop one axis" you get a (degenerate) polytope with B(n-1) symmetry, with nodes either "up","down","zero", or in "both" positions of the dropped direction. (Since D3=A3, the simplest example is a tetrahedron being seen as an alternated cube, looking like a square in the plane.) So at least this means the simple integer coordinates exists in (n-1) coordinates, but the nth coordinate can be offset by a (possibly) irrational distance. Maybe this helps? Tom Ruen (talk) 15:51, 20 November 2010 (UTC)
 * [[File:Geometric folding Coxeter graphs.png]][[File:A3 polyhedra ortho.png]]

D3 generating vectors? (folded B2)

 * 1) [[File:CDW_dot.png]][[File:CDW_3b.png]][[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_dot.png]] --> [[File:CDW_ring.png]][[File:CDW_4.png]][[File:CDW_dot.png]] : (2,0,0) [all]
 * 2) [[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_dot.png]][[File:CDW_3b.png]][[File:CDW_ring.png]] --> [[File:CDW_dot.png]][[File:CDW_4.png]][[File:CDW_ring.png]] : (2,2,0) [all]
 * 3) [[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_dot.png]][[File:CDW_3b.png]][[File:CDW_dot.png]] --> [[File:CDW_dot.png]][[File:CDW_4.png]][[File:CDW_hole.png]] : (1,1,1) [half]

SUM:
 * 1) [[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_dot.png]] --> [[File:CDW_ring.png]][[File:CDW_4.png]][[File:CDW_hole.png]] : (2,0,0) + (1,1,1) = (3,1,1) [half]
 * 2) [[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_ring.png]] --> [[File:CDW_ring.png]][[File:CDW_4.png]][[File:CDW_ring.png]] : (2,2,0) + (2,0,0) = (4,2,0) [all]

D4 generating vectors? (folded B3)

 * 1) [[Image:CD_ring.png]][[Image:CD_3b.png]][[Image:CD_downbranch-00.png]][[Image:CD_3b.png]][[Image:CD_dot.png]] --> [[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_dot.png]][[File:CDW_4.png]][[File:CDW_dot.png]] : (2,0,0,0) [all]
 * 2) [[Image:CD_dot.png]][[Image:CD_3b.png]][[Image:CD_downbranch-10.png]][[Image:CD_3b.png]][[Image:CD_dot.png]] --> [[File:CDW_dot.png]][[File:CDW_3b.png]][[File:CDW_ring.png]][[File:CDW_4.png]][[File:CDW_dot.png]] : (2,2,0,0) [all]
 * 3) [[Image:CD_dot.png]][[Image:CD_3b.png]][[Image:CD_downbranch-01.png]][[Image:CD_3b.png]][[Image:CD_ring.png]] --> [[File:CDW_dot.png]][[File:CDW_3b.png]][[File:CDW_dot.png]][[File:CDW_4.png]][[File:CDW_ring.png]] : (2,2,2,0) [all]
 * 4) [[Image:CD_dot.png]][[Image:CD_3b.png]][[Image:CD_downbranch-01.png]][[Image:CD_3b.png]][[Image:CD_dot.png]] --> [[File:CDW_dot.png]][[File:CDW_3b.png]][[File:CDW_dot.png]][[File:CDW_4.png]][[File:CDW_hole.png]] : (1,1,1,1) [half]

SUM:
 * 1) [[Image:CD_ring.png]][[Image:CD_3b.png]][[Image:CD_downbranch-11.png]][[Image:CD_3b.png]][[Image:CD_ring.png]] --> [[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_ring.png]][[File:CDW_4.png]][[File:CDW_ring.png]] : (2,0,0,0) + (2,2,0,0) + (2,2,2,0) = (6,4,2,0) [all]
 * 2) [[Image:CD_ring.png]][[Image:CD_3b.png]][[Image:CD_downbranch-11.png]][[Image:CD_3b.png]][[Image:CD_dot.png]] --> [[File:CDW_ring.png]][[File:CDW_3b.png]][[File:CDW_ring.png]][[File:CDW_4.png]][[File:CDW_hole.png]] : (2,0,0,0) + (2,2,0,0) +(1,1,1,1) = (4,3,1,1) [half]
 * 3) [[Image:CD_dot.png]][[Image:CD_3b.png]][[Image:CD_downbranch-11.png]][[Image:CD_3b.png]][[Image:CD_ring.png]] --> [[File:CDW_dot.png]][[File:CDW_3b.png]][[File:CDW_ring.png]][[File:CDW_4.png]][[File:CDW_ring.png]] : (2,2,0,0) + (2,2,2,0) = (4,4,2,0) [all]

As best I can tell, these are correct, and should extend to any dimension!

I added them to the table at Demitesseract family. The edge lengths are sqrt(2).

Tom Ruen (talk) 18:48, 20 November 2010 (UTC)

folding

 * The 122 is related to the 24-cell by a geometric folding of the Coxeter-Dynkin diagrams.

(And elsewhere.) Do you plan to explain that? —Tamfang (talk) 01:17, 24 November 2010 (UTC)


 * I hope so! So far just a note at Talk:Coxeter_number, and paper . (Also 421 and 600-cell from E8--> H4) So the relation is "projectional", from the right basis, you can "remove coordinates" and get the lower dimensional form, but only shown as shared 2d coxeter plane projections. I partly used this relation to extract demicube truncation polytope coordinates from truncated cubes Dn --> B(n-1). These reductions might also be useful for drawing symmetry directions of the higher uniform honeycombs. Tom Ruen (talk) 01:54, 24 November 2010 (UTC)

help - deleting images
Is there any EASY way to mark a set of images for deletion? I used to upload a set, and I used the wrong file names. Leaving them is harmless (they are technically correct), but I'd hope this could be cleaned up (without hand-marking every one, like with  !!!) Thanks! Tom Ruen (talk) 00:57, 25 November 2010 (UTC)

File:1 22 t0 B2.svg File:1 22 t01 B2.svg File:1 22 t1 B2.svg File:1 22 t2 B2.svg File:1 22 t3 B2.svg File:2 21 t0 B2.svg File:2 21 t01 B2.svg File:2 21 t1 B2.svg File:2 21 t2 B2.svg File:1 22 t0 B3.svg File:1 22 t01 B3.svg File:1 22 t1 B3.svg File:1 22 t2 B3.svg File:1 22 t3 B3.svg File:2 21 t0 B3.svg File:2 21 t01 B3.svg File:2 21 t1 B3.svg File:2 21 t2 B3.svg File:1 22 t0 B4.svg File:1 22 t01 B4.svg File:1 22 t1 B4.svg File:1 22 t2 B4.svg File:1 22 t3 B4.svg File:2 21 t0 B4.svg File:2 21 t01 B4.svg File:2 21 t1 B4.svg File:2 21 t2 B4.svg File:1 22 t0 B5.svg File:1 22 t01 B5.svg File:1 22 t1 B5.svg File:1 22 t2 B5.svg File:1 22 t3 B5.svg File:2 21 t0 B5.svg File:2 21 t01 B5.svg File:2 21 t1 B5.svg File:2 21 t2 B5.svg File:1 22 t0 B6.svg File:1 22 t01 B6.svg File:1 22 t1 B6.svg File:1 22 t2 B6.svg File:1 22 t3 B6.svg File:2 21 t0 B6.svg File:2 21 t01 B6.svg File:2 21 t1 B6.svg File:2 21 t2 B6.svg
 * Yeah, I can delete them all for you, but it's better just to rename them. Did you reupload them correctly or shall I rename them? (You'll need to tell me what to call them.) / ƒETCH COMMS  /  01:13, 25 November 2010 (UTC)


 * Actually, I can't delete them (they're on Commons) but I can still rename them for you. Just tell me what they should be called. / ƒETCH COMMS  /  01:14, 25 November 2010 (UTC)


 * Thanks so much! RENAMING might work for some, but there's actually two problems, some aren't useful, and also my upload utility failed to replace some older ones that were mis-colored. Is it possible to delete all File:1_22*.svg and File:2_21*.svg images uploaded by me? Then I could reupload the correct set. Tom Ruen (talk) 01:21, 25 November 2010 (UTC)


 * OH, I just saw your second reply. :( What can be done? Tom Ruen (talk) 01:23, 25 November 2010 (UTC)
 * OK, if you need to delete them from Commons, tag them with or something similar. Unfortunately, I'm not a Commons admin, so I can't delete them. / ƒETCH  COMMS  /  01:30, 25 November 2010 (UTC)


 * Okay, so I'm back where I started, need to hand-mark some 100 files to be deleted. Should I contact a common admin, who perhaps can do a mass delete in one step? Tom Ruen (talk) 01:37, 25 November 2010 (UTC)
 * That would probably be best. I'm sure there's some sort of script they can use. / ƒETCH COMMS  /  01:49, 25 November 2010 (UTC)

Talkback: Nils von Barth: Dynkin diagram folding

 * (Another one.)


 * (Short reply.)


 * (Short thanks!)

Coxeter-Dynkin diagrams - rendering issue
Hi Tom,

Just passed by the List of E8 polytopes and for me the Coxeter-Dynkin diagrams are breaking onto two lines. My screen is not quite high enough resolution to show the columns at full width, so Firefox is flowing the individual pieces onto extra lines instead of overflowing to the right.

One fix might be to put each piece in a cell of a nested table, something like this for the first one:

which looks OK:

Don't know if it's possible to tidy up the CSS with an in-page stylesheet and classes?

&mdash; Cheers, Steelpillow (Talk) 21:11, 4 December 2010 (UTC)


 * Thanks Guy for the look and suggestion. So the table will prevent breakup? Another user was looking at macros, so symbols could be expanded, and you could say, and it could expand to the file names, so that could be extended to expand a tight-table formating like you suggested too!


 * But it seems primarily the problem is the "failed SVG" files show up as file names in FireFox, while just X graphics in IE, so the names force the columns wider than they need to be. So I should remove those links, just been too lazy. (The problem is SVG files FAIL to render (converted to PNG bitmaps) if larger than about 6megs. I fixed some by only generating vertices, not edges, but when the vertices themselves exceed 6M, its game over for SVG, unless it is fixed.) Tom Ruen (talk) 00:44, 5 December 2010 (UTC)


 * Yes, a row of table cells never breaks - it just extends rightwards. Otherwise, tables of values would become a real mess - like Oracle PL/SQL query results on a dumb terminal used to. You could alternatively create extra columns for the main table and use the colspan attribute for the heading and legends, but I find nested tables easier to work with.


 * I'd probably implement all C-D diagrams using a single "universal" template with parser functions or similar, something like
 * and able to handle up to say 20 symbols or whatever is a reasonable maximum.
 * and able to handle up to say 20 symbols or whatever is a reasonable maximum.


 * I was not aware of the SVG issue. It is not relevant to the breakup problem I am seeing. However, I am not clear on the value of using giant SVG files here. I guess the Commons might be expected to cope, but Wikipedia might equally be forgiven for barfing on what is otherwise beng used as a 92 dpi online illustration.
 * &mdash; Cheers, Steelpillow (Talk) 15:07, 5 December 2010 (UTC)


 * Really, still a problem? I had removed the dead images which saved some space. A general length template would be great, but I'm not sure I'm smart enough to make variable length expansion. But not too many families, so maybe templates (CD_A2...CD_A10, CD_B2..CD_B10, CD_D4..CD_D10, CD_E6..CD_E8, CD_F4) wouldn't be too ugly. Tom Ruen (talk) 13:12, 6 December 2010 (UTC)
 * I reduced images to 40px, so that maybe is enough? Tom Ruen (talk) 13:15, 6 December 2010 (UTC)


 * Tom, the issue is not one of compressing the table width down to some arbitrary screen size. There will always be people whose screens are smaller than that, or who increase the text and image sizes for readability. I happen to prefer to size my browser at approx. 3/4 my desktop screen width, leaving other tools visible. The only way to keep the diagrams intelligible for such visitors is to stop them breaking up (the diagrams that is, not the visitors).
 * An example of a variable rate expansion is template:familytree and friends. If you are still stuck, I could probably knock something up, but have very little time available.
 * &mdash; Cheers, Steelpillow (Talk) 17:46, 6 December 2010 (UTC)

table-fu
See User talk:Stephen2nd/Royal Labels of the United Kingdom. You seem to know more about table format than I do. Can you get rid of the horizontal white hairline? (A label, in this context, is a mark to distinguish the coat-of-arms of a younger son.) —Tamfang (talk) 01:55, 6 December 2010 (UTC)


 * Good attempt! I played a bit also, no dice for me either. Tom Ruen (talk) 12:55, 6 December 2010 (UTC)

Someone else succeeded. —Tamfang (talk) 20:51, 6 December 2010 (UTC)

Help math
I know how to make these symbols for affine Dynkin diagram group names:
 * $${\tilde{A}}_{n}$$ = $${\tilde{A}}_{n}$$

Is there a way to make the ~ larger and cross two letters?
 * $${\tilde{AB}}_{n}$$ = $${\tilde{AB}}_{n}$$

Tom Ruen (talk) 06:33, 16 December 2010 (UTC)


 * I've read through Help:Displaying a formula, but I don't think there's a way to do what you want. The only alternative I can think of to show that the ~ is over two variables is to use parentheses, like this:


 * $${\tilde{(AB)}}_{n}$$ = $${\tilde{(AB)}}_{n}$$


 * I'll leave the tag in case someone else has a better answer.  --Mysdaao talk 13:50, 16 December 2010 (UTC)
 * As no one else has answered, you may get a swifter response at WP:VPT. / ƒETCH COMMS  /  16:34, 16 December 2010 (UTC)


 * Hi Tom Ruen,
 * The way to do this is to use \widetilde. $${\widetilde{AB}}_{n}$$ = $${\widetilde{AB}}_{n}$$
 * Unfortunately, widetilde is not accepted by texvc, a computer program that preprocesses TeX formulas for MediaWiki (the software that runs Wikipedia).
 * You could ask the maintainers of texvc to make the change:
 * Go to texvc.
 * Click the link, texvc bugs.
 * Click the link, File a new bug in the "MediaWiki extensions" product.
 * Log in to Bugzilla. :(I don't have a user account with Bugzilla yet. Unfortunately, getting one reveals my e-mail address.):
 * Type a bug description.

Add support for \widetilde. Currently, texvc has support for \widehat but not \widetilde. This might be possible to add with a simple change to texutil.ml. Add a line: | "\\widehat"         -> LITERAL (TEX_ONLY "\\widehat ")
 * --Kevinkor2 (talk) 06:18, 21 December 2010 (UTC)


 * Cool! I tried this. Tom Ruen (talk) 06:30, 21 December 2010 (UTC)

Template magic?
See Template:Railway line legend for a similar concept. They may be able to help you get started. Kaldari (talk) 05:23, 19 December 2010 (UTC)


 * Hi Tomruen,
 * I've been watching Kaldari's page (since I left a message on it), and I saw your request and was intrigued.
 * I have made a template in my user space. Maybe this is what you want:
 * produced by the code:
 * One basic feature of my template is that it can take lots of positional parameters, and it uses a parser function to ignore parameters that aren't present:
 * Another feature of my template is that it uses a helper template, CD2, to expand dot and ring.
 * --Kevinkor2 (talk) 14:30, 19 December 2010 (UTC)
 * Another feature of my template is that it uses a helper template, CD2, to expand dot and ring.
 * --Kevinkor2 (talk) 14:30, 19 December 2010 (UTC)
 * --Kevinkor2 (talk) 14:30, 19 December 2010 (UTC)

Thanks Kevinkor2, works well! And I combined another suggestion of putting in a unpadded table to avoid mid-symbol wrapping, and that worked too! Tom Ruen (talk) 00:00, 20 December 2010 (UTC)
 * (Template:CDW and Template:CDW-el), (Template:CD and Template:CD-el), (Template:CDT and Template:CDT-el)
 * a=, b=, c=, d=

OH, except that it seems to adds a CR??? I don't know how to mix macros and tables without side effects. Tom Ruen (talk) 00:18, 20 December 2010 (UTC)


 * Maybe its just an HTML limitation - tables can't flow with text. Tom Ruen (talk) 00:25, 20 December 2010 (UTC)


 * Hi Tom,
 * We are both trying to work on this at the same time! :)
 * --Kevinkor2 (talk) 08:27, 20 December 2010 (UTC)


 * I'm sorry! Keep trying (without table)! I don't see what's right, but found at least. Tom Ruen (talk) 08:29, 20 December 2010 (UTC)


 * Test case: see how this wraps:                  --Kevinkor2 (talk) 08:35, 20 December 2010 (UTC)

This works at least: Tom Ruen (talk) 08:39, 20 December 2010 (UTC)


 * Yay! It also works across browsers: I've tried it with IE7, IE8, Chrome, Safari, and Firefox. :) I'll next change the CD and CDT templates to match. --Kevinkor2 (talk) 08:53, 20 December 2010 (UTC)

THANKS SO MUCH! Tom Ruen (talk) 08:56, 20 December 2010 (UTC)
 * ps. Good idea - I see you can use comment-blocks to "hide" CRs in the template definition, which is easier to read and edit! Tom Ruen (talk) 08:58, 20 December 2010 (UTC)


 * Yay! I think we've got it!!! --Kevinkor2 (talk) 08:59, 20 December 2010 (UTC)


 * Hi Tom, found your message, came up with an answer - much clunkier than this, so go with it! &mdash; Cheers, Steelpillow (Talk) 09:17, 20 December 2010 (UTC)

About the lunar eclipse time stamp
Thing is I'm not completely sure at what time I took the picture since the date on my camera was inaccurate. I did try remembering however and ended up with 8:30 UTC (more or less) — Preceding unsigned comment added by Aaron1a12 (talk • contribs) 22:26, 22 December 2010 (UTC)


 * If the camera clock is functional you can take a picture of a clock, and compare the clock time in the picture to the timestamp and calculate a time difference, and use that to adjust the datestamp from other pictures. Tom Ruen (talk) 22:57, 22 December 2010 (UTC)

"with a single nodea_1 on the end of the 1-node branch."
Did you do a mass replacement of "ring" with "nodea_1"? —Tamfang (talk) 18:23, 30 December 2010 (UTC)


 * OH, did I overwrite something outside the templates? Tom Ruen (talk) 21:24, 30 December 2010 (UTC)


 * yep. I fixed a few, I see you're fixing some others. —Tamfang (talk) 01:06, 31 December 2010 (UTC)


 * Thanks for the look. Good thing most of the articles I touched were lists, so minimal text to mangle! Tom Ruen (talk) 01:15, 31 December 2010 (UTC)

File has no license
Hi! I noticed you removed the license on this file File:Uniform dual tiling 433-t2.png. The file need a license so perhaps it was a mistake? If yes you can just add the license again and forget this notice :-) --MGA73 (talk) 18:35, 3 January 2011 (UTC)