Steenrod squares

Steenrod squares

[′sten‚räd ′skwerz]
(mathematics)
Operations which associate elements from different cohomology groups of a topological space and produce an element in another of the groups; these operations can be so added and multiplied as to produce the Steenrod algebra.
References in periodicals archive ?
The isomorphism [kappa] preserves cup products and Steenrod squares so that:
Again, as k commutes with Steenrod squares, we see that
Among the topics discussed by the research articles are symplectic Heegaard splittings and linked abelian groups, differential characters and the Steenrod squares, relative weight filtrations on completions of mapping class groups, symplectic automorphism groups of nilpotent quotient of fundamental groups of surfaces, and new examples of elements in the kernel of the Magnus representation of the Torelli groups.
0 may be chosen to extend the square S*(X) [cross product] a S*(X) [arrow right] S*(X) induced by the Alexander-Whitney map, and defines the Steenrod squares {[Sq.
Now, the Steenrod squares are also defined on the cohomology of the cocommutative Hopf algebras over Z/p, in particular, the Ext of the Steenrod algebras [L1][My]: Let A be a cocommutative Hopf algebra over Z/2, e.