A correspondence $I$ from from an AbstractVariety $X$ (the source of $I$) to another AbstractVariety $Y$ (the target of $I$) consists of two functions $I_*$ and $I^*$, which take cycles on $X$ to cycles on $Y$ and vice-versa, respectively. In general these functions are not ring maps or even module maps. See Correspondence ^* and Correspondence _* for more info.
Unlike an IncidenceCorrespondence, a general Correspondence need not have an intermediate variety.
The object Correspondence is a type, with ancestor classes MutableHashTable < HashTable < Thing.
The source of this document is in /build/reproducible-path/macaulay2-1.25.05+ds/M2/Macaulay2/packages/Schubert2.m2:1857:0.