Skip to main content
23 events
when toggle format what by license comment
Oct 4, 2022 at 4:18 comment added Z. M @DmitriPavlov Thanks. If it is lawful, maybe also add a link in ncatlab.org/nlab/show/Fr%C3%A9chet+manifold#Losik94 and wikipedia page (there is a footnote for Losik's paper) en.wikipedia.org/wiki/Diffeology
Oct 4, 2022 at 0:31 comment added Dmitri Pavlov @Z.M: Losik's paper is available here: dmitripavlov.org/scans/…
Oct 1, 2022 at 18:27 history made wiki Post Made Community Wiki by Stefan Kohl
Oct 1, 2022 at 5:03 comment added Alec Rhea I agree that abandoning excluded middle would be ambitious for a 10th grade class, to say the least haha -- the texts I had in mind were Synthetic Geometry of Manifolds and Synthetic Differential Geometry by Anders Kock.
Sep 30, 2022 at 21:55 comment added Dmitri Pavlov @Z.M: A translation does exist, but it appears that Springer's online archive only covers years from 2007 on. I ordered it through my library.
Sep 30, 2022 at 21:06 comment added Z. M @DmitriPavlov Do you have any English material which summarizes that proof? There seems no English translation of that paper. I only find an article by the same author which summarizes the theorems but not the proofs.
Sep 30, 2022 at 20:30 comment added Arshak Aivazian @AlecRhea The fact is that I give my students a course on differential geometry and, in parallel, a course on the theory of sheaves (more precisely, sheaves on sites and Grothendieck topoi). I would like to use the powerful mechanism of sheaves to construct all the missing spaces, but I would not want the only place where the differential geometry lives for them is only non-classical topoi. I consider constructive mathematics fundamentally more natural and important, but nevertheless it seems inappropriate (today) to force students in the 10th grade to abandon the law of the excluded middle.
Sep 30, 2022 at 20:30 comment added Arshak Aivazian @AlecRhea Thank you, I like synthetic differential geometry and I will definitely study it! I have several texts, but please send yours - perhaps I will find new and interesting ones among them. However, it doesn't work for me right now.
Sep 30, 2022 at 19:42 comment added Dmitri Pavlov @Z.M: The Banach or Fréchet structure can be canonically recovered from the sheaf structure (on finite-dimensional manifolds), see the paper of Losik “Fréchet manifolds as diffeological spaces”. It proves that the category of Fréchet manifolds embeds fully faithfully in the category of diffeological spaces.
Sep 30, 2022 at 19:33 vote accept Arshak Aivazian
Sep 30, 2022 at 19:23 comment added Z. M @DmitriPavlov Thanks. But I am not sure whether this recovers the "infinite-dimensional manifold" structure, or even the topological structure. For example, if we take some form of "geometric realization" of a sheaf in the category of topological spaces, it is a co-end, thus a colimit of finite dimensional manifolds, so there is no Banach structure (on the tangent spaces) or something like this.
Sep 30, 2022 at 18:48 comment added Dmitri Pavlov @Z.M: The category of sheaves of sets (or simplicial sets) on the site of smooth manifolds is a cartesian closed category. In particular, the internal hom Hom(M,N) between two smooth manifolds M and N exists and has the expected properties. For example, the tangent space at any point can be computed as relative vector fields along a smooth map, etc. Likewise, the Lie algebra of the (infinite-dimensional) group of diffeomorphisms M→M can be computed as the Lie algebra of vector fields on M. The book by Iglesias-Zemmour explains all this.
Sep 30, 2022 at 18:28 history became hot network question
Sep 30, 2022 at 18:22 comment added Alec Rhea Is synthetic differential geometry appealing to you? The general setting is a topos (sometimes Grothendieck, sometimes just well-pointed or even less than a topos works) — I have a few good texts in mind if that sounds interesting.
Sep 30, 2022 at 17:14 comment added Z. M I wonder the relation of the first sentence (about infinite-dimensional manifolds) and the later. If I understand correctly, smooth spaces / stacks are finitary in nature.
Sep 30, 2022 at 17:00 comment added Andy Putman I agree with @ChrisGerig here in the sense that this is not how mainstream people working in differential geometry conceive of their subject. This is not to say that it might not be useful for whatever it is you're trying to do, just that any such book won't help you read the differential geometry literature.
Sep 30, 2022 at 15:52 answer added Dmitri Pavlov timeline score: 12
Sep 30, 2022 at 15:12 comment added Arshak Aivazian @ChrisGerig I don't understand what you mean.
Sep 30, 2022 at 14:45 comment added Chris Gerig I'd go as far to say you're not really doing differential geometry anymore...
Sep 30, 2022 at 12:01 history edited Arshak Aivazian CC BY-SA 4.0
added 3 characters in body
Sep 30, 2022 at 10:46 history edited Arshak Aivazian CC BY-SA 4.0
added 2 characters in body
Sep 30, 2022 at 10:35 history edited Arshak Aivazian CC BY-SA 4.0
added 13 characters in body
Sep 30, 2022 at 10:27 history asked Arshak Aivazian CC BY-SA 4.0