proposition: Remark ell_sigma_support M g : M \in 'M -> g \in M^~~ -> \ell_\sigma(g) <= 2.
proof: Proof. by move=> maxM /bigcupP[x Msx]; apply: ell_sigma_cover; apply: Msigma_ell1 Msx. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrbool ssrfun eqtype ssrnat seq div path fintype bigop order) mathcomp(finset prime fingroup morphism perm automorphism quotient) mathcomp(action gproduct gfunctor pgroup cyclic center commutator) mathcomp(gseries nilpotent sylow abelian maximal hall frobenius) mathcomp(ssralg ssrnum ssrint rat) odd_order(BGsection1 BGsection3 BGsection4 BGsection5 BGsection6) odd_order(BGsection7 BGsection9 BGsection10 BGsection12 BGsection13)