proposition: Lemma eq_inv_scale (V : lmodType R) (s : R) (x y : V) : s != 0 -> (x == s^-1 *: y) = (s *: x == y).
proof: Proof. exact: (fun _ => esym (can2_eq (scalerK _) (scalerKV _) _ _)). Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrbool ssrfun ssrnat eqtype seq order) mathcomp(fintype bigop) mathcomp(ssralg ssrnum matrix) mathcomp(zmodp) GeoCoq.Axioms.tarski_axioms GeoCoq.Axioms.gupta_inspired_variant_axioms GeoCoq.Meta_theory.Models.gupta_inspired_to_tarski GeoCoq.Meta_theory.Counter_models.coplanarity GeoCoq.Meta_theory.Parallel_postulates.parallel_postulates GeoCoq.Tarski_dev.Ch12_parallel_inter_dec