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D.4.8.17 kontrahom
Procedure from library homolog.lib (see homolog_lib).
- Usage:
- kontrahom(A,k); A=matrix, k=integer
- Return:
- matrix Hom(A,R^k), i.e. let A be a matrix defining a map F1-->F2 of
free R-modules, then the matrix of Hom(F2,R^k)-->Hom(F1,R^k) is
computed (R=basering).
Example:
| | LIB "homolog.lib";
ring r;
matrix n[2][3]=x,y,5,z,77,33;
print(kontrahom(n,3));
==> x,z, 0,0, 0,0,
==> y,77,0,0, 0,0,
==> 5,33,0,0, 0,0,
==> 0,0, x,z, 0,0,
==> 0,0, y,77,0,0,
==> 0,0, 5,33,0,0,
==> 0,0, 0,0, x,z,
==> 0,0, 0,0, y,77,
==> 0,0, 0,0, 5,33
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