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Mirrors > Home > MPE Home > Th. List > bitr4i | Structured version Visualization version GIF version |
Description: An inference from transitive law for logical equivalence. (Contributed by NM, 3-Jan-1993.) |
Ref | Expression |
---|---|
bitr4i.1 | ⊢ (𝜑 ↔ 𝜓) |
bitr4i.2 | ⊢ (𝜒 ↔ 𝜓) |
Ref | Expression |
---|---|
bitr4i | ⊢ (𝜑 ↔ 𝜒) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | bitr4i.1 | . 2 ⊢ (𝜑 ↔ 𝜓) | |
2 | bitr4i.2 | . . 3 ⊢ (𝜒 ↔ 𝜓) | |
3 | 2 | bicomi 223 | . 2 ⊢ (𝜓 ↔ 𝜒) |
4 | 1, 3 | bitri 274 | 1 ⊢ (𝜑 ↔ 𝜒) |
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