Friday, 19 December 2008

at.algebraic topology - Fiber bundle = principal bundle + fiber?

This question is heavily related to this question.



Fix a sufficiently nice and connected topological space B and let FB be the category of fiber bundles over B. A morphism f:(EtoB)to(EtoB) in this category is a map EtoE over B and hence it maps fibers to fibers.



Edit: A fiber bundle p:EtoB is a continuous map such that there exists a local trivialization. Since B is nice and connected, all the fibers p1(x) are isomorphic.



According to the very helpful answers here,



  • a fiber bundle over B with fiber F determines a G=Aut(F)-principal bundle together with (trivially) a left G-action on F and

  • a G-principal bundle over B, where G is an arbitrary topological group, together with a topological space F and a left G-action on F determines a fiber bundle over B with fiber F.

Can one formulate this correspondence "categorically", i.e. is there an equivalence of the category FB to a product (?) of two categories, one encoding the "glueing structure" (the principal bundle) and one encoding the "fiber information" (the space F with the action)? (In particular, what should be the analogue to a morphism of fiber bundles?)



(Certainly is not possible to get such a description precisely like above because one have to fix the topological group G to say what a space F with a G-action is and conversely one have to fix a space F to say what a G=Aut(F)-principal bundle is, but maybe there is a way to formulate this in general.)

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