Metamath Proof Explorer


Theorem tsan1

Description: A Tseitin axiom for logical conjunction, in deduction form. (Contributed by Giovanni Mascellani, 24-Mar-2018)

Ref Expression
Assertion tsan1 ( 𝜃 → ( ( ¬ 𝜑 ∨ ¬ 𝜓 ) ∨ ( 𝜑𝜓 ) ) )

Proof

Step Hyp Ref Expression
1 pm3.12 ( ( ¬ 𝜑 ∨ ¬ 𝜓 ) ∨ ( 𝜑𝜓 ) )
2 1 a1i ( 𝜃 → ( ( ¬ 𝜑 ∨ ¬ 𝜓 ) ∨ ( 𝜑𝜓 ) ) )