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Mirrors > Home > ILE Home > Th. List > or4 | GIF version |
Description: Rearrangement of 4 disjuncts. (Contributed by NM, 12-Aug-1994.) |
Ref | Expression |
---|---|
or4 | ⊢ (((𝜑 ∨ 𝜓) ∨ (𝜒 ∨ 𝜃)) ↔ ((𝜑 ∨ 𝜒) ∨ (𝜓 ∨ 𝜃))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | or12 761 | . . 3 ⊢ ((𝜓 ∨ (𝜒 ∨ 𝜃)) ↔ (𝜒 ∨ (𝜓 ∨ 𝜃))) | |
2 | 1 | orbi2i 757 | . 2 ⊢ ((𝜑 ∨ (𝜓 ∨ (𝜒 ∨ 𝜃))) ↔ (𝜑 ∨ (𝜒 ∨ (𝜓 ∨ 𝜃)))) |
3 | orass 762 | . 2 ⊢ (((𝜑 ∨ 𝜓) ∨ (𝜒 ∨ 𝜃)) ↔ (𝜑 ∨ (𝜓 ∨ (𝜒 ∨ 𝜃)))) | |
4 | orass 762 | . 2 ⊢ (((𝜑 ∨ 𝜒) ∨ (𝜓 ∨ 𝜃)) ↔ (𝜑 ∨ (𝜒 ∨ (𝜓 ∨ 𝜃)))) | |
5 | 2, 3, 4 | 3bitr4i 211 | 1 ⊢ (((𝜑 ∨ 𝜓) ∨ (𝜒 ∨ 𝜃)) ↔ ((𝜑 ∨ 𝜒) ∨ (𝜓 ∨ 𝜃))) |
Colors of variables: wff set class |
Syntax hints: ↔ wb 104 ∨ wo 703 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 704 |
This theorem depends on definitions: df-bi 116 |
This theorem is referenced by: or42 767 orordi 768 orordir 769 3or6 1318 swoer 6539 apcotr 8519 |
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