proposition: Lemma eq_div_scale (V : lmodType R) (s1 s2 : R) (x y : V) : s2 != 0 -> (x == (s1 / s2) *: y) = (s2 *: x == s1 *: y).
proof: Proof. by move=> s2_neq0; rewrite -scalerA -eq_inv_scale// !scalerA mulrC. 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