GAP Manual: 25.52. Igs

Igs( U )

Igs returns an induced generating system of U with respect to the parent group of U as list of ag words (see More about Ag Groups).

If U.igs is bound, this is returned without any further action. If U.cgs but not U.igs is bound, this is returned. If neither U.igs nor U.cgs are bound, an induced generating system for U is computed using MergedIgs (see MergedIgs) and bound to U.igs.