Theorem bj-currypeirce 33894

Description: Curry's axiom curryax 890 (a non-intuitionistic positive statement sometimes called a paradox of material implication) implies Peirce's axiom peirce 204 over minimal implicational calculus and the axiomatic definition of disjunction (actually, only the elimination axiom jao 957 via its inference form jaoi 853; the introduction axioms olc 864 and orc 863 are not needed). Note that this theorem shows that actually, the standard instance of curryax 890 implies the standard instance of peirce 204, which is not the case for the converse bj-peircecurry 33895. (Contributed by BJ, 15-Jun-2021.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
bj-currypeirce	⊢ ((𝜑 ∨ (𝜑 → 𝜓)) → (((𝜑 → 𝜓) → 𝜑) → 𝜑))

Proof of Theorem bj-currypeirce

Step	Hyp	Ref	Expression
1		ax-1 6	. 2 ⊢ (𝜑 → (((𝜑 → 𝜓) → 𝜑) → 𝜑))
2		pm2.27 42	. 2 ⊢ ((𝜑 → 𝜓) → (((𝜑 → 𝜓) → 𝜑) → 𝜑))
3	1, 2	jaoi 853	1 ⊢ ((𝜑 ∨ (𝜑 → 𝜓)) → (((𝜑 → 𝜓) → 𝜑) → 𝜑))

Syntax hints:   → wi 4   ∨ wo 843

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 209  df-or 844

This theorem is referenced by: (None)