One of the key features of a labeled module is that it comes equipped with a list of modules used in its construction. For instance, if $F$ is the tensor product of $A$ and $B$, then the underlying modules of $F$ would be the set $\{ A,B\}$. Similarly, if $G=\wedge^2 A$, then $A$ is the only underlying module of $G$.
i1 : S=ZZ/101[x,y,z]; |
i2 : A=labeledModule(S^2); o2 : free S-module with labeled basis |
i3 : B=labeledModule(S^5); o3 : free S-module with labeled basis |
i4 : F=A**B 10 o4 = S o4 : free S-module with labeled basis |
i5 : underlyingModules(F) 2 5 o5 = {S , S } o5 : List |
i6 : G=exteriorPower(2,A) 1 o6 = S o6 : free S-module with labeled basis |
i7 : underlyingModules(G) 2 o7 = {S } o7 : List |
The object underlyingModules is a method function.