In algebraic topology, the slant product is the following pairing between singular homology and singular cohomology:
It is induced at the chains/cochains level by the Eilenberg-Zilber chain map
When the abelian group has a commutative ring structure, one can take and postcompose with to obtain the pairing
In particular, for one obtains the contraction
taking values in the coefficient ring of the given cohomology theory.