proposition: Theorem wem_proof_irrelevance_cci : forall (B:Prop) (b1 b2:B), ~~b1 = b2.
proof: Proof. exact (wproof_irrelevance_cc or or_introl or_intror or_ind or_elim_redl or_elim_redr or_indd wem). Qed.
imports: PropExtensionalityFacts Hurkens