fact: Definition eltm of #[y] %| #[x] := fun x_i => y ^+ invm (injm_Zpm x) x_i.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice div) mathcomp(fintype bigop prime finset fingroup morphism) mathcomp(perm automorphism quotient gproduct ssralg) mathcomp(finalg zmodp poly)