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D.7.1.32 secondary_not_cohen_macaulay
Procedure from library finvar.lib (see finvar_lib).
- Usage:
- secondary_not_cohen_macaulay(P,G1,G2,...[,v]);
P: a 1xn <matrix> with primary invariants, G1,G2,...: nxn <matrices>
generating a finite matrix group, v: optional <int>
- Assume:
- n is the number of variables of the basering
- Return:
- secondary invariants of the invariant ring (type <matrix>)
- Display:
- information on the progress of computation if v does not equal 0
- Theory:
- Secondary invariants are generated following "Generating Invariant
Rings of Finite Groups over Arbitrary Fields" by Kemper (1996).
Example:
| LIB "finvar.lib";
ring R=2,(x,y,z),dp;
matrix A[3][3]=0,1,0,-1,0,0,0,0,-1;
list L=primary_invariants(A);
matrix S=secondary_not_cohen_macaulay(L[1],A);
print(S);
==> 1
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