D.4.28.2 isSymmetric

Usage:

isSymmetric(I,sigma); I ideal, sigma intvec

Assume:

size(sigma) = nvars(basering) =: n

Return:

1, if the set of generators of I is invariant under sigma;
0, if the set of generators of I is not invariant under sigma

Note:

sigma is a permutation of the variables of the basering, i.e.
sigma: var(i) ----> var(sigma[i]), 1 <= i <= n.

LIB "symodstd.lib";
ring R = 0,x(1..5),dp;
ideal I = cyclic(5);
intvec pi = 2,3,4,5,1;
isSymmetric(I,pi);
==> 1
intvec tau = 2,5,1,4,3;
isSymmetric(I,tau);
==> 0