fact: Definition perm_f (g f: {ffun 'I_k -> 'I_l}) := if goodP g f isn't ReflectT b then 1%g else Perm (inv_g_of_fx_inj (proj1 b) (proj2 b)).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice finfun) mathcomp(matrix bigop zmodp mxalgebra fingroup) minor