PropExtensionality.v

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This module states propositional extensionality and draws consequences of it

Axiom propositional_extensionality :
  forall (P Q : Prop), (P <-> Q) -> P = Q.

Require Import ClassicalFacts.

Theorem proof_irrelevance : forall (P:Prop) (p1 p2:P), p1 = p2.forall (P : Prop) (p1 p2 : P), p1 = p2
Proof.forall (P : Prop) (p1 p2 : P), p1 = p2
  apply ext_prop_dep_proof_irrel_cic.prop_extensionality
  exact propositional_extensionality.
Qed.