proposition: Lemma gee0_abs x : 0 <= x -> `|x| = x.
proof: Proof. by move: x => [x| |]//; rewrite lee_fin => x0; apply/eqP; rewrite eqe ger0_norm. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra) signed