Wikipedia:Reference desk/Archives/Mathematics/2022 June 19

= June 19 =

German translation
Famous Kronecker quote:
 * Die ganzen Zahlen hat der liebe Gott gemacht, alles andere ist Menschenwerk

I think "ganzen Zahlen" translates literally do "exact numbers". Is it a normal German mathematical term, and does it mean integers? Or only the nonnegative integers aka natural numbers? Thanks. 2601:648:8202:350:0:0:0:90B2 (talk) 21:14, 19 June 2022 (UTC)
 * It literally translates as "[the] whole numbers" – all else being fractions (literally "broken" numbers). I suppose he was thinking of the natural numbers. Today we know, of course, that these were created by Giuseppe Peano. --Lambiam 21:30, 19 June 2022 (UTC)
 * I suppose your last claim is slightly facetious; the natural numbers were understood in the sense of being well-specified long before they were ever axiomatized. Actually, today we know that God also created the entire universe of set theory, containing choice functions and large cardinals. --Trovatore (talk) 16:25, 20 June 2022 (UTC)
 * Yes, I meant to imply by this that the natural numbers are (IMO) just as much Menschenwerk as alles andere, using Peano as a representative of the class Mensch. --Lambiam 19:53, 20 June 2022 (UTC)
 * Ah thanks. I'm only familiar with the ultrafinitist version of Peano arithmetic, where the integers go from 1 to 88.  2601:648:8202:350:0:0:0:90B2 (talk) 21:43, 19 June 2022 (UTC)
 * Splorch is only 88? --Trovatore (talk) 16:39, 20 June 2022 (UTC)
 * My literal translation: "The dear God has made the whole numbers, all else is man's work." I don't know if the original context is available; the quote is taken from an obituary by Heinrich Weber. But Kronecker was famously a finitist and distrusted mathematics that could not be related to the integers, for example the set theory of Georg Cantor. An (uncited) quote of Kronecker in Controversy over Cantor's theory says "I don't know what predominates in Cantor's theory – philosophy or theology, but I am sure that there is no mathematics there." --RDBury (talk) 03:52, 20 June 2022 (UTC)
 * Thanks, yeah, I mistranslated "ganze" instead of "genau" and wondered what was going on. 2601:648:8202:350:0:0:0:90B2 (talk) 06:10, 20 June 2022 (UTC)
 * Ganz genau. I forgot to mention that ganze Zahl is (also today) a normal German mathematical term, as seen in phrases like "" ("Let $n$ be a whole number." — in the context an element of $Z$.) Also, German Mensch is gender-neutral. --Lambiam 07:39, 20 June 2022 (UTC)
 * Yes, but "man" in that sense is also gender-neutral. --Trovatore (talk) 16:05, 20 June 2022 (UTC)
 * It may be useful to add a footnote saying that here the sense is gender-neutral, because it is not necessarily obvious.
 * It's amusing to contrast this with Gian-Carlo Rota's quote, "God created infinity, and man, unable to understand infinity, had to invent finite sets."--2406:E003:812:5001:996C:7D19:F588:DF6C (talk) 11:45, 21 June 2022 (UTC)
 * Heh, see also the category-theoretic "parable of the shepherds":
 * Long ago, when shepherds wanted to see if two herds of sheep were isomorphic, they would look for an explicit isomorphism. In other words, they would line up both herds and try to match each sheep in one herd with a sheep in the other. But one day, along came a shepherd who invented decategorification. She realized one could take each herd and "count" it, setting up an isomorphism between it and some set of "numbers", which were nonsense words like "one, two, three,..." specially designed for this purpose. By comparing the resulting numbers, she could show that two herds were isomorphic without explicitly establishing an isomorphism! In short, by decategorifying the category of finite sets, the set of natural numbers was invented. 2601:648:8202:350:0:0:0:90B2 (talk) 22:50, 21 June 2022 (UTC)