Theorem bitr3 344

Description: Closed nested implication form of bitr3i 269. Derived automatically from bitr3VD 39902. (Contributed by Alan Sare, 31-Dec-2011.)

Assertion

Ref	Expression
bitr3	⊢ ((𝜑 ↔ 𝜓) → ((𝜑 ↔ 𝜒) → (𝜓 ↔ 𝜒)))

Proof of Theorem bitr3

Step	Hyp	Ref	Expression
1		bibi1 343	. 2 ⊢ ((𝜑 ↔ 𝜓) → ((𝜑 ↔ 𝜒) ↔ (𝜓 ↔ 𝜒)))
2	1	biimpd 221	1 ⊢ ((𝜑 ↔ 𝜓) → ((𝜑 ↔ 𝜒) → (𝜓 ↔ 𝜒)))

Syntax hints:   → wi 4   ↔ wb 198

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 199

This theorem is referenced by:  sumodd  15492  3orbi123VD  39903  sbc3orgVD  39904  trsbcVD  39930  csbrngVD  39949  e2ebindVD  39965  e2ebindALT  39982