All Questions
1 question
8
votes
1
answer
374
views
Analogue of Bockstein for crossed module extensions and higher Steenrod square
It is well known that in $\mathbb{Z}_2$-valued simplicial cohomology (and other cohomologies)
$$ Sq^1 = \beta\;,$$
where $Sq^1$ is the first Steenrod square and $\beta$ is the Bockstein homomorphism ...