proposition: Lemma lemma4 : g (conj c * conj a * d * conj b) = conj a * d.
proof: Proof. unfold g. rewrite 2 simple_associativity. rewrite <- simple_associativity. rewrite left_inverse. rewrite right_identity. rewrite 2 simple_associativity. rewrite right_inverse. rewrite <- simple_associativity. apply left_identity. Defined.
imports: Classes.interfaces.abstract_algebra Cubical Pointed.Core Pointed.pSusp Homotopy.HSpace.Core Homotopy.Suspension Homotopy.Join.Core