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Mirrors > Home > MPE Home > Th. List > 3bitr4i | Structured version Visualization version GIF version |
Description: A chained inference from transitive law for logical equivalence. This inference is frequently used to apply a definition to both sides of a logical equivalence. (Contributed by NM, 3-Jan-1993.) |
Ref | Expression |
---|---|
3bitr4i.1 | ⊢ (𝜑 ↔ 𝜓) |
3bitr4i.2 | ⊢ (𝜒 ↔ 𝜑) |
3bitr4i.3 | ⊢ (𝜃 ↔ 𝜓) |
Ref | Expression |
---|---|
3bitr4i | ⊢ (𝜒 ↔ 𝜃) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 3bitr4i.2 | . 2 ⊢ (𝜒 ↔ 𝜑) | |
2 | 3bitr4i.1 | . . 3 ⊢ (𝜑 ↔ 𝜓) | |
3 | 3bitr4i.3 | . . 3 ⊢ (𝜃 ↔ 𝜓) | |
4 | 2, 3 | bitr4i 277 | . 2 ⊢ (𝜑 ↔ 𝜃) |
5 | 1, 4 | bitri 274 | 1 ⊢ (𝜒 ↔ 𝜃) |
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