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Mirrors > Home > MPE Home > Th. List > anbi12i | Structured version Visualization version GIF version |
Description: Conjoin both sides of two equivalences. (Contributed by NM, 12-Mar-1993.) |
Ref | Expression |
---|---|
anbi12.1 | ⊢ (𝜑 ↔ 𝜓) |
anbi12.2 | ⊢ (𝜒 ↔ 𝜃) |
Ref | Expression |
---|---|
anbi12i | ⊢ ((𝜑 ∧ 𝜒) ↔ (𝜓 ∧ 𝜃)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | anbi12.1 | . . 3 ⊢ (𝜑 ↔ 𝜓) | |
2 | 1 | anbi1i 623 | . 2 ⊢ ((𝜑 ∧ 𝜒) ↔ (𝜓 ∧ 𝜒)) |
3 | anbi12.2 | . . 3 ⊢ (𝜒 ↔ 𝜃) | |
4 | 3 | anbi2i 622 | . 2 ⊢ ((𝜓 ∧ 𝜒) ↔ (𝜓 ∧ 𝜃)) |
5 | 2, 4 | bitri 274 | 1 ⊢ ((𝜑 ∧ 𝜒) ↔ (𝜓 ∧ 𝜃)) |
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