User talk:Quartl

POTD notification
Hi Quartl,

Just to let you know that the Featured Picture File:Polygonia c-album qtl2.jpg is due to make an appearance as Picture of the Day on January 22, 2013. If you get a chance, you can check and improve the caption at Template:POTD/2013-01-22. — howcheng  {chat} 23:29, 20 January 2013 (UTC)

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Hi Quartl,

Just to let you know that the Featured Picture File:Attacus atlas qtl1.jpg is due to make an appearance as Picture of the Day on August 3, 2013. If you get a chance, you can check and improve the caption at Template:POTD/2013-08-03. Thank you for all of your contributions! — Crisco 1492 (talk) 00:47, 19 July 2013 (UTC)

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Hi Quartl,

Just to let you know that the Featured Picture File:Anax imperator qtl2.jpg is due to make an appearance as Picture of the Day on August 8, 2013. If you get a chance, you can check and improve the caption at Template:POTD/2013-08-08. Thank you for all of your contributions! — Crisco 1492 (talk) 22:48, 22 July 2013 (UTC)

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Hi Quartl,

Just to let you know that the Featured Picture File:Kallima inachus qtl1.jpg is due to make an appearance as Picture of the Day on December 13, 2013. If you get a chance, you can check and improve the caption at Template:POTD/2013-12-13. Thank you for all of your contributions! — Crisco 1492 (talk) 22:52, 27 November 2013 (UTC)

POTD notification


Hi Quartl,

Just to let you know that the Featured Picture File:Dendrobates azureus qtl1.jpg is due to make an appearance as Picture of the Day on December 19, 2013. If you get a chance, you can check and improve the caption at Template:POTD/2013-12-19. Thank you for all of your contributions! — Crisco 1492 (talk) 23:26, 29 November 2013 (UTC)

Today's featured picture
Wow what a great photo. Congratulations on File:Kallima inachus qtl1.jpg and "Today's featured picture". Well done! Thank you. -SusanLesch (talk) 15:05, 13 December 2013 (UTC)


 * Thank you :-), --Quartl (talk) 16:50, 13 December 2013 (UTC)

Working together
Hello. I am Lfahlberg. Sorry to be so lengthy.

I think it is important that math articles contain all different levels of (accurate) information about the subject. I am interested in collaborating with others and in improving the math pages on the English wikipedia. They are regularly used and also serve as translation pages. (I work on the MK math pages; I have lived and worked in MK for almost 40 years.)
 * I have a Ph.D. in theoretical mathematics so I am not incompetent in higher mathematics. However, it doesn't really interest me.
 * I work mainly in ICT in math education; I have taught under-graduate and post-graduate engineering mathematics for over 35 years. My brother and I pioneered math movies (mathcasts) long before Khan and I have math YouTube channels in English and Macedonian and I was the GeoGebra YouTube channel up until last year.
 * I really do know alot about mathematics at the middle-school (6-12) and university level, particularly for engineering and technology students and what they don't understand and need to know. The students are not stupid, but they are so confused from 12 years of mish-mash schooling.

I don't want to do is the theoretical stuff. I think it is important to have this - just not at the beginning and it requires alot of care, which I am not interested in.
 * So my question is: Is there anyway we could collaborate usefully? Or do you know anyone else interested in such a collaboration? Not just to do the theoretical stuff, but to check the lower-level stuff and give useful suggestions so that the pages really do work?

BTW: I also liked the point that someone made in the project page that we need to add information for professionals who need information about math topics and its problems (e.g. I think I noticed that care was taken to include this information on the wikipedia page for Newton-Raphson's root-finding method and its problems for professionals (but I might be confused and might have seen it elsewhere).

I should "warn" you that I am the type of person who thinks that some images and examples even on a wikipedia page are extremely important and that e.g. knowing that &pi;/2 &asymp; 1.5 is important. (Working on trigonometry stuff so this was the first example that came to mind.)
 * If you are interested in collaborating:
 * I would appreciate knowing whether the definition you gave on the Talk:Linear_equation talk page is indeed a generalization of the low-level definition given in the Linear equation page itself? If so, I think we should add it under generalizations. And I presume there are other generalizations?
 * Also, as I have mentioned several times, linear equations are lines only if they have exactly two real-valued variables (with non-zero coefficients :)). This is incredibly confusing to engineering students who cannot plot z=x+y and try to solve systems of linear equations laboring under the wrong idea that all linear equations are lines.

Sorry to go on and on. (Should have been IM's first clue that I am actually an old woman - hah.) Lfahlberg (talk) 12:28, 6 January 2014 (UTC)


 * Sorry, as you might have seen from my contributions I am not terribly active in the English language wikipedia. I mainly work in the German language wikipedia, though I do often come here for for cross-checks and I tend to observe the articles on subjects I contributed to in :de. I did write de:Lineare Gleichung (you can try google translate, but from the formulas it's easy to see what is going on), but the article is more algebraic than the one here. Probably it would be best to have two articles: Line equation, which takes a geometric approach, and Linear equation, which takes an algebraic approach. That's why I made the comment on the talk page. Best wishes, --Quartl (talk) 13:55, 6 January 2014 (UTC)


 * Thank-you for your reply. Lfahlberg (talk) 14:58, 6 January 2014 (UTC)

DYK for 100 prisoners problem
— Crisco 1492 (talk) 11:38, 14 July 2014 (UTC)

Edit to Matrix multiplication
Hi Quartl, I'd like to comment on your revert of my edit. Good to know that there are people who take the time to double-check, and you're right in that this property is only valid for commutative rings, I didn't know that. I still think that it would be worth mentioning this property somewhere, with a mention of the commutative ring requirement of course. It's necessary e. g. for deriving least squares, where you can then write yTXβ + βTXTy = 2βTXTy. Also, it's useful to know that you can switch left and right vectors for a symmetric matrix with real-valued entries. If you agree, where do you think would be the best place for it? The location of my original edit was not optimal, since this doesn't require the matrix to be square. Maybe Transpose? Cheers, Allion (talk) 15:31, 1 February 2015 (UTC)
 * Hi Allion, I'm not sure where to put this property. Basically it is a combination of two properties. The first one is the general transpose rule (A1A2...Ak−1Ak)T = AkTAk−1T...A2TA1T, which is mentioned in Transpose but not in Matrix multiplication where one would also expect it. The second one is AT = A for 1×1 matrices, which is mentioned in neither article, maybe because it's too trivial. Maybe a good place would be Matrix multiplication? Best wishes, --Quartl (talk) 16:20, 1 February 2015 (UTC)

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ArbCom elections are now open!
Hi, You appear to be eligible to vote in the current Arbitration Committee election. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to enact binding solutions for disputes between editors, primarily related to serious behavioural issues that the community has been unable to resolve. This includes the ability to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate, you are welcome to review the candidates' statements and submit your choices on the voting page. For the Election committee, MediaWiki message delivery (talk) 14:06, 24 November 2015 (UTC)