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Theorem ts3an1 38832
Description: A Tseitin axiom for triple logical conjunction, in deduction form. (Contributed by Giovanni Mascellani, 25-Mar-2018.)
Assertion
Ref Expression
ts3an1 (𝜃 → ((¬ (𝜑𝜓) ∨ ¬ 𝜒) ∨ (𝜑𝜓𝜒)))

Proof of Theorem ts3an1
StepHypRef Expression
1 tsan1 38823 . 2 (𝜃 → ((¬ (𝜑𝜓) ∨ ¬ 𝜒) ∨ ((𝜑𝜓) ∧ 𝜒)))
2 df-3an 1105 . . 3 ((𝜑𝜓𝜒) ↔ ((𝜑𝜓) ∧ 𝜒))
32orbi2i 926 . 2 (((¬ (𝜑𝜓) ∨ ¬ 𝜒) ∨ (𝜑𝜓𝜒)) ↔ ((¬ (𝜑𝜓) ∨ ¬ 𝜒) ∨ ((𝜑𝜓) ∧ 𝜒)))
41, 3sylibr 237 1 (𝜃 → ((¬ (𝜑𝜓) ∨ ¬ 𝜒) ∨ (𝜑𝜓𝜒)))
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  ¬ wn 3  wi 4  wa 401  wo 861  w3a 1103
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8
This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105
This theorem is used by: (None)
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