Timeline for On similar concepts in mathematics whose similarity is a non-trivial fact.

8 events

when toggle format	what		by	license	comment
Dec 24, 2012 at 6:30	vote	accept	Leonard
Dec 19, 2012 at 19:06	history	edited	Peter Michor	CC BY-SA 3.0	added 46 characters in body
Dec 19, 2012 at 18:17	comment	added	Todd Trimble		If the nLab gives a correct reference, then Boman proved it in 1967. Reference: Jan Boman, Differentiability of a function and of its compositions with functions of one variable, Math. Scand. 20 1967 249–268.
Dec 19, 2012 at 10:11	history	edited	Peter Michor	CC BY-SA 3.0	Added more
Dec 19, 2012 at 3:47	comment	added	Paul Siegel		I can't believe the result is really that recent: I've seen a version of (2) as a definition of smoothness in old differential geometry books. Aside from that, I remember this being assigned as a homework problem in an analysis class; it's harder than it seems at first, but it just came down to compactness of the circle if I recall correctly.
Dec 19, 2012 at 2:13	comment	added	Leonard		Very interesting indeed! Looks trivial, but after looking at the actual proof, I am deeply impressed by its depth.
Dec 18, 2012 at 21:30	comment	added	Todd Trimble		Wow! That's interesting.
Dec 18, 2012 at 19:09	history	answered	Peter Michor	CC BY-SA 3.0