hom

Usage:
    <hom a b c
The module Hom(a,b) is put into the
variable c.
Parameters:
            a,b = modules
Output values:
            c = Hom(a,b)
We will compute Hom as the kernel of
the map
               f = Hom(a,B)
            Hom(A0,B)  ------------>  Hom(A1,B), where
where b is a presentation of B and
           a
                    A1 --> A0
is a.
    The script returns a standard basis