fact: Definition narrow := ('r_p(A) > 2) ==> ('E_p^2(A) :&: 'E*_p(A) != set0).
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrbool ssrfun eqtype ssrnat seq div) mathcomp(fintype finset prime fingroup morphism perm automorphism action) mathcomp(quotient cyclic gfunctor pgroup gproduct center commutator) mathcomp(gseries nilpotent sylow abelian maximal hall) odd_order(BGsection1 BGsection4)