fact: Hypotheses (defG : GH \* GK = G) (ziGHK : GH :&: GK = 'Z(GH)).
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq div) mathcomp(fintype bigop finset fingroup morphism perm) mathcomp(automorphism quotient action gproduct gfunctor) mathcomp(cyclic)