Usage:
<hom_is_0 a b
The output is the null matrix
iff Hom is 0. Useful for
checking whether an element is a
nonzerodivisor (but the script NZD does it a different way.)
Parameters:
a,b modules
This version of the script hom is optimized for testing
hom for 0.
Modulo is used in place of the
call to <kernel in the script Hom, and reduce is used
to make the test. For further description, see hom.