Theorem tsxo4 38992

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

Assertion

Ref	Expression
tsxo4	⊢ (𝜃 → ((¬ 𝜑 ∨ 𝜓) ∨ (𝜑 ⊻ 𝜓)))

Proof of Theorem tsxo4

Step	Hyp	Ref	Expression
1		tsbi4 38988	. 2 ⊢ (𝜃 → ((¬ 𝜑 ∨ 𝜓) ∨ ¬ (𝜑 ↔ 𝜓)))
2		df-xor 1542	. . . 4 ⊢ ((𝜑 ⊻ 𝜓) ↔ ¬ (𝜑 ↔ 𝜓))
3	2	bicomi 227	. . 3 ⊢ (¬ (𝜑 ↔ 𝜓) ↔ (𝜑 ⊻ 𝜓))
4	3	orbi2i 926	. 2 ⊢ (((¬ 𝜑 ∨ 𝜓) ∨ ¬ (𝜑 ↔ 𝜓)) ↔ ((¬ 𝜑 ∨ 𝜓) ∨ (𝜑 ⊻ 𝜓)))
5	1, 4	sylib 221	1 ⊢ (𝜃 → ((¬ 𝜑 ∨ 𝜓) ∨ (𝜑 ⊻ 𝜓)))

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ↔ wb 209   ∨ wo 861   ⊻ wxo 1541

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-or 862  df-xor 1542

This theorem is used by: (None)