GAP Manual: 25.50. AgSubgroup

AgSubgroup( U, gens, flag )

Let U be an ag group with ag group G, gens be an induct or canonical generating system for a subgroup S of U and flag a boolean. Then AgSubgroup returns the record of an ag group representing this finite polycyclic group S as subgroup of G.

If flag is true, gens must be a canonical generating with respect to G. If flag is false gens must be a an induced generating with respect to G.

gens will be bound to S.generators. If flag is true, it is also bound to S.cgs, if it is false, gens is also bound to S.igs. Note that AgSubgroup does not copy gens.

Note that it is not check whether gens are an induced or canonical system. If gens fails to be one, all following computations with this group are most probably wrong.

    gap> v4 := AgSubgroup( s4, [ c, d ], true );
    Subgroup( s4, [ c, d ] )