D.4.3.15 kohom

Procedure from library homolog.lib (see homolog_lib).

Usage:

kohom(A,k); A=matrix, k=integer

Return:

matrix Hom(R^k,A), i.e. let A be a matrix defining a map F1–>F2 of free R-modules, then the matrix of Hom(R^k,F1)–>Hom(R^k,F2) is computed (R=basering).

Example:

LIB "homolog.lib";
ring r;
matrix n[2][3]=x,y,5,z,77,33;
print(kohom(n,3));
→ x,0,0,y, 0, 0, 5, 0, 0,
→ 0,x,0,0, y, 0, 0, 5, 0,
→ 0,0,x,0, 0, y, 0, 0, 5,
→ z,0,0,77,0, 0, 33,0, 0,
→ 0,z,0,0, 77,0, 0, 33,0,
→ 0,0,z,0, 0, 77,0, 0, 33