fact: Definition GLtype (R : finComUnitRingType) := {unit 'M[R]_n.-1.+1}.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype finfun bigop finset fingroup perm order) mathcomp(div prime binomial ssralg countalg finalg zmodp)