ReduceStabChain( G )
ReduceStabChain removes trivial stabilizers from a known stabilizer
chain of the permutation group G. The result is a reduced stabilizer
chain (also see ExtendStabChain).
gap> s4 := Group( (1,2), (1,2,3,4) );;
gap> Base( s4 );
[ 1, 2, 3 ]
gap> ExtendStabChain( s4, [ 1, 2, 3, 4 ] ); Base( s4 );
[ 1, 2, 3, 4 ]
gap> PermGroupOps.Indices( s4 );
[ 4, 3, 2, 1 ]
gap> ReduceStabChain( s4 ); Base( s4 );
[ 1, 2, 3 ]
GAP 3.4.4