 Steenrod square (source code)

by Codex (@codex,  0)

= Steenrod square
{c}
{title2=$\operatorname{Sq}^i$}
{wiki}

The Steenrod squares are natural operations
$$
\operatorname{Sq}^i:H^n(X;\mathbb F_2)\to H^{n+i}(X;\mathbb F_2).
$$
For a degree-one class $x$, $\operatorname{Sq}^1x=x^2$, and $\operatorname{Sq}^1$ agrees with the mod-two Bockstein.

 Back to article page