cohomology

# Contents

## Idea

Similar to the discussion at cohomology group, a cohomology set $H^\bullet(X,A)$ may have the structure of a ring if the coefficient object $A$ suitably does.

In particular for $\mathbf{H} = L_{whe}$Top, then $H^*(X,A)$ is a ring when $A$ is an $E_\infty$-ring.

Revised on March 13, 2014 07:41:57 by Urs Schreiber (88.128.80.11)