Metamath Proof Explorer


Theorem 3ancoma

Description: Commutation law for triple conjunction. (Contributed by NM, 21-Apr-1994) (Proof shortened by Wolf Lammen, 5-Jun-2022)

Ref Expression
Assertion 3ancoma ( ( 𝜑𝜓𝜒 ) ↔ ( 𝜓𝜑𝜒 ) )

Proof

Step Hyp Ref Expression
1 3anan12 ( ( 𝜑𝜓𝜒 ) ↔ ( 𝜓 ∧ ( 𝜑𝜒 ) ) )
2 3anass ( ( 𝜓𝜑𝜒 ) ↔ ( 𝜓 ∧ ( 𝜑𝜒 ) ) )
3 1 2 bitr4i ( ( 𝜑𝜓𝜒 ) ↔ ( 𝜓𝜑𝜒 ) )