Spahn sheaf on a sheaf (Rev #2)

Motivation

Let XHX\in H be a space (an object of a category HH of spaces), let Sh(X)Sh(X) be the category of sheaves on the frame of opens on XX, let (H/X) et(H/X)^{et} denote the wide subcategory of H/XH/X with only étale morphisms. Then there is an adjoint equivalence

(LΓ):(H/X) etΓSh(X)(L\dashv \Gamma):(H/X)^{et}\stackrel{\Gamma}{\to}Sh(X)

where

  • Γ\Gamma sends an étale morphism f:UXf:U\to X to the sheaf of local sections of ff.

  • LL sends a sheaf on XX to its espace étale.

Très petit topos

We wish to clarify in which sense also the (,1)(\infty,1)- topos (H/X) fet(H/X)^{fet} can be regarded as an (,1)(\infty,1)-sheaftopos on XX.

Revision on December 15, 2012 at 19:34:11 by Stephan Alexander Spahn?. See the history of this page for a list of all contributions to it.