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Timeline for Composition of bibundles

Current License: CC BY-SA 4.0

18 events
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Nov 30, 2023 at 8:18 history edited David Roberts CC BY-SA 4.0
Fixed small error
Nov 27, 2023 at 5:46 comment added David Roberts @Connor thanks! I should fix it.
Nov 27, 2023 at 4:06 comment added Connor Grady I just wanted to point out a small error in the second paragraph in case anyone else gets confused like I did. Namely that $\mathbf{B}G$ should not act trivially on $u(H)$, it should act via $\phi$. This is implicit in the next paragraph though, so no harm, no foul :)
Sep 27, 2018 at 7:56 comment added Praphulla Koushik You said "No, you don't think about the H-bundle $P\times H\rightarrow P$, all bundles you are considering should be over M. Why not ask another question..." Yes.. I was thinking something else.. I understand that and added that in my answer. Thanks..
Sep 26, 2018 at 10:46 comment added Praphulla Koushik Let us continue this discussion in chat.
Sep 26, 2018 at 6:41 comment added Praphulla Koushik I do not know how to read your comment as :P I understand the point more clearly after rewriting your answer... Thanks :D
Sep 26, 2018 at 6:38 comment added David Roberts You have indeed faithfully rewritten my answer using different notation :-)
Sep 26, 2018 at 6:18 comment added Praphulla Koushik Thanks. I will see that. Do you think I got the rough idea correctly atleast?
Sep 26, 2018 at 6:13 comment added David Roberts en.wikipedia.org/wiki/Associated_bundle gives a hint, but if you can access it, this is definitive: doi.org/10.1007/978-1-4757-2261-1_6. Or see Definition 5.5 in the sequel, mathematik.uni-muenchen.de/~schotten/Texte/…
Sep 26, 2018 at 6:01 comment added Praphulla Koushik I have written in my words what you said. Let me know if I have missed anything. I am not very comfortable with changing the structure group along a morphism of Lie groups. If you can suggest some reference for the same it will be helpful.
Sep 26, 2018 at 4:13 comment added Praphulla Koushik Ok.. I am also trying to rewrite your answer in my own words and in my own notation so that I can appreciate it more than what I do now.. I do not mean I am editing your answer... Your explanation is super clear and I have no doubt about that...
Sep 26, 2018 at 4:09 comment added David Roberts I'm not sure what else I would say. I prefer my counterexample to your counterexample, as it is shorter and less confusing to me.
Sep 26, 2018 at 2:40 comment added Praphulla Koushik Can you check my other replies to this question as answers. YOur comments would be helpful..
Sep 11, 2018 at 3:35 vote accept Praphulla Koushik
Jul 15, 2018 at 12:46 comment added David Roberts The notation $\mathbf{B}G$ means the Lie groupoid whose object manifold is $\{pt\}$ and whose arrow manifold is denoted $G$. It follows from the axioms that $G$ is nothing else than a Lie group. If I were to write the stack of $G$-bundles, which is the stackification of this Lie groupoid, I would write it as $\mathrm{Bun}_G$ or similar.
Jul 6, 2018 at 20:17 comment added Praphulla Koushik I am having little difficulty with the notations.. When you say “BG is one-object Lie groupoid” you mean $G$ is a Lie group, we have a groupoid associated to a Lie group, object set is Singleton, morphism set is G, usually written as $\{G\rightrightarrows *\}$.. you are calling this associated Lie groupoid also by G and then you are considering stack associated to Lie groupoid G(in your notation) and calling it BG. Is this correct? Or are you calling Lie groupoid it self by $BG$?
Jul 4, 2018 at 12:23 comment added Praphulla Koushik Hello, I am with so much pending work :( I will respond in 2/3 days. Apologies. Thanks for your answer. I am sure it will make a difference :)
Jul 4, 2018 at 3:33 history answered David Roberts CC BY-SA 4.0