Theorem subord2-P4.RC 563

Description: Inference Form of subord2-P4 562. †

Hypotheses

Ref	Expression
subord2-P4.RC.1	⊢ (𝜑 ∨ 𝜒)
subord2-P4.RC.2	⊢ (𝜑 ↔ 𝜓)
subord2-P4.RC.3	⊢ (𝜒 ↔ 𝜗)

Assertion

Ref	Expression
subord2-P4.RC	⊢ (𝜓 ∨ 𝜗)

Proof of Theorem subord2-P4.RC

Step	Hyp	Ref	Expression
1		subord2-P4.RC.1	. . . 4 ⊢ (𝜑 ∨ 𝜒)
2	1	ndtruei-P3.17 182	. . 3 ⊢ (⊤ → (𝜑 ∨ 𝜒))
3		subord2-P4.RC.2	. . . 4 ⊢ (𝜑 ↔ 𝜓)
4	3	ndtruei-P3.17 182	. . 3 ⊢ (⊤ → (𝜑 ↔ 𝜓))
5		subord2-P4.RC.3	. . . 4 ⊢ (𝜒 ↔ 𝜗)
6	5	ndtruei-P3.17 182	. . 3 ⊢ (⊤ → (𝜒 ↔ 𝜗))
7	2, 4, 6	subord2-P4 562	. 2 ⊢ (⊤ → (𝜓 ∨ 𝜗))
8	7	ndtruee-P3.18 183	1 ⊢ (𝜓 ∨ 𝜗)

Syntax hints:   ↔ wff-bi 104   ∨ wff-or 144  ⊤wff-true 153

This theorem was proved from axioms:  ax-L1 11  ax-L2 12  ax-L3 13  ax-MP 14

This theorem depends on definitions:  df-bi-D2.1 107  df-and-D2.2 133  df-or-D2.3 145  df-true-D2.4 155  df-rcp-AND3 161

This theorem is referenced by: (None)