proposition: Lemma compsP G s : reflect (last G s = 1%G /\ path [rel x y : gTg | maxnormal y x x] G s) (comps G s).
proof: Proof. by apply: (iffP andP) => [] [/eqP]. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype bigop finset fingroup morphism) mathcomp(automorphism quotient action gseries)