Matrix ** Module

f ** N -- tensor product of a matrix f and a module N.
N ** f -- tensor product of a matrix f and a module N.

This is the same as tensoring f with the identity map of N.

When N is a free module of rank 1 the net effect of the operation is to shift the degrees of f .

     i1 = R = ZZ/101[t]
     
     o1 = R
     
     o1 : PolynomialRing

     i2 = f = matrix {{t}}
     
     o2 = | t |
     
                  1       1
     o2 : Matrix R  <--- R

     i3 = degrees source f
     
     o3 = {{1}}
     
     o3 : List

     i4 = degrees source (f ** R^{-3})
     
     o4 = {{4}}
     
     o4 : List