Theorem frege53aid 38993

Description: Specialization of frege53a 38994. Proposition 53 of [Frege1879] p. 50. (Contributed by RP, 24-Dec-2019.) (Proof modification is discouraged.)

Assertion

Ref	Expression
frege53aid	⊢ (𝜑 → ((𝜑 ↔ 𝜓) → 𝜓))

Proof of Theorem frege53aid

Step	Hyp	Ref	Expression
1		frege52aid 38992	. 2 ⊢ ((𝜑 ↔ 𝜓) → (𝜑 → 𝜓))
2		ax-frege8 38943	. 2 ⊢ (((𝜑 ↔ 𝜓) → (𝜑 → 𝜓)) → (𝜑 → ((𝜑 ↔ 𝜓) → 𝜓)))
3	1, 2	ax-mp 5	1 ⊢ (𝜑 → ((𝜑 ↔ 𝜓) → 𝜓))

Syntax hints:   → wi 4   ↔ wb 198

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-frege8 38943  ax-frege52a 38991

This theorem depends on definitions:  df-bi 199  df-an 387  df-or 881  df-ifp 1092  df-tru 1662  df-fal 1672

This theorem is referenced by: (None)