Skip to main content
7 events
when toggle format what by license comment
Aug 10, 2020 at 22:22 comment added Connor Malin It is true that $p$ is the j homomorphism. $Bp$ classifies taking a vector bundle to its sphere bundle thought of as a block bundle, while $Bj$ classifies taking a vector bundle to its sphere bundle. The equivalence you describe $B\widetilde{TOP}(S^3) \rightarrow BG(S^3)$ classifies taking a spherical block bundle to an equivalent fibration (which is a spherical fibration). So the evident diagram commutes showing p is the J-homomorphism.
Jan 21, 2015 at 22:29 history edited student CC BY-SA 3.0
added 267 characters in body
Jan 21, 2015 at 22:11 comment added student oop!I see your point.$S^n$ is just Topologically rigid,but not smoothly rigid.Now I want to switch from the category from Diff to Top,and the problem still makes sense.
Jan 21, 2015 at 22:06 comment added Oscar Randal-Williams I don't think this argument can be right: why should $S(M)$ be contractible? (Which is what I suppose you mean by "trivial".)
Jan 21, 2015 at 21:32 comment added student well,even if this is true,i guess what this argument proved is:For every $S^3$ block bundle over $S^4$,there exists a concordant block bundle which admits fiber bundle structure.This is weaker than the property appeared in the the original problem.
Jan 21, 2015 at 21:13 history edited student CC BY-SA 3.0
added 2 characters in body
Jan 21, 2015 at 21:07 history answered student CC BY-SA 3.0