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D.4.4.4 cardGroup
Procedure from library cisimplicial.lib (see cisimplicial_lib).
- Usage:
- cardGroup(A[,n]); A is a matrix with integral coefficients.
- Return:
- It returns a bigint. If we denote by ZA the group generated
by the columns of the matrix A, then it returns the number of
elements of the group of Z^m / ZA, where m = number of rows of A.
If a second parameter n is introduced, it will
only consider the first n columns of A. It returns 0 if Z^m / ZA
is infinite; this is, when rank ZA < m.
Example:
| | LIB "cisimplicial.lib";
intmat A[3][5] = 24, 0, 0, 8, 3,
0, 24, 0, 10, 6,
0, 0, 24, 5, 9;
cardGroup(A);
==> 72
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