Theorem pm5.36

Description: Theorem *5.36 of WhiteheadRussell p. 125. (Contributed by NM, 3-Jan-2005)

	Ref	Expression
Assertion	pm5.36	⊢ ( ( 𝜑 ∧ ( 𝜑 ↔ 𝜓 ) ) ↔ ( 𝜓 ∧ ( 𝜑 ↔ 𝜓 ) ) )

Proof

Step	Hyp	Ref	Expression
1		id	⊢ ( ( 𝜑 ↔ 𝜓 ) → ( 𝜑 ↔ 𝜓 ) )
2	1	pm5.32ri	⊢ ( ( 𝜑 ∧ ( 𝜑 ↔ 𝜓 ) ) ↔ ( 𝜓 ∧ ( 𝜑 ↔ 𝜓 ) ) )