fact: Definition maxainv (B C : {set rT}) := [max C of H | [&& (H <| B), ~~ (B \subset H) & [acts A, on H | to]]].
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype bigop finset fingroup morphism) mathcomp(automorphism quotient action gseries)