proposition: Lemma inj_strictf (p q : nat) (f: 'I_p -> 'I_q) : strictf f -> injective f.
proof: Proof. move/forallP=> /= hf x y heq. move/forallP: (hf x) => /= hfx. move/forallP: (hf y) => /= hfy. case: (ltngtP x y)=> [||h]; last by apply/ord_inj. by rewrite (eqP (hfx y)) heq ltnn. by rewrite (eqP (hfy x)) heq ltnn. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice finfun) mathcomp(matrix bigop zmodp mxalgebra fingroup) minor