Schreiber differential cohomology - abelian case

This is a subentry of the entry differential cohomology.

We discuss here how the general theory of differential nonabelian cohomology developed there relates to the standard theory of abelian differential cohomology.

raw material for the moment

The crucial input for translating the general setup to the familar abelian differential cohomology setup is

• the “naturality of the differential Quillen adjunction” as discussed at path ∞-groupoid which gives commutative diagram

$\array{ Y &\to & A_{flat} \\ \downarrow && \downarrow \\ \Pi(Y) &\to& A }$

and their version for the infinitesimal path ∞-groupoid?

$\array{ Y &\to & A_{flat}^{inf} \\ \downarrow && \downarrow \\ \Pi^{inf}(Y) &\to& A }$
• the deRham theorem for ∞-Lie groupoids? which for $A = \mathbf{B}^n \mathbb{R}$ identifies

• $Y \to A_{flat}^{inf}$ with a degree $n$ real cococyle;

• $\Pi^{inf}(Y) \to A$ with the corresponding deRham cocycle.

Ordinary abelian differential cohomology starts (following Hopkins-Singer) with specifying real cohomology classes

$\iota : A \to \mathbf{B}^n\mathbb{R}_{c}$

on an abelian $A$, then pulling these back along a given $A$-cocycle $g : Y \to A$ to the composite

$Y \stackrel{g}{\to} A \stackrel{\iota}{\to} \mathbf{B}^n\mathbb{R}_{c}$

and then identifying them there by a homotopy $h$ with a differential form

$\array{ Y &\stackrel{g}{\to}& A &\stackrel{\iota}{\to}& \mathbf{B}^n\mathbb{R}_c \\ \downarrow &&&& \downarrow \\ \Pi^{inf}(Y) &\stackrel{\omega}{\to}&&\to& \mathbf{B}^n\mathbb{R} }$
Created on September 29, 2009 12:57:41 by Urs Schreiber (195.37.209.182)