traceMap F
If $F$ is a free labeled module, then this produces the trace map $S\to F\otimes F^*$.
i1 : S=ZZ/101[x,y,z];
i2 : F=labeledModule(S^3); o2 : free S-module with labeled basis
i3 : traceMap F o3 = | 1 | | 0 | | 0 | | 0 | | 1 | | 0 | | 0 | | 0 | | 1 | 9 1 o3 : Matrix S <--- S
The object traceMap is a method function.