"Homomorphisms.txt" computes homomorphisms between two D-modules, D is a differential ring, for example, D=C(x,y)[dx,dy]
                        
"projHom" gives a 1-dimentional module s.t. after tensor with it, two input modules are homomorphic.

"eg of hom" gives some examples to compute D-module homomorphisms.

"eg of projHom" give some example of projective homomorphisms.