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| Mirrors > Home > MPE Home > Th. List > bitr4id | Structured version Visualization version GIF version | ||
| Description: A syllogism inference from two biconditionals. (Contributed by NM, 25-Nov-1994.) |
| Ref | Expression |
|---|---|
| bitr4id.2 | ⊢ (𝜓 ↔ 𝜒) |
| bitr4id.1 | ⊢ (𝜑 → (𝜃 ↔ 𝜒)) |
| Ref | Expression |
|---|---|
| bitr4id | ⊢ (𝜑 → (𝜓 ↔ 𝜃)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | bitr4id.1 | . 2 ⊢ (𝜑 → (𝜃 ↔ 𝜒)) | |
| 2 | bitr4id.2 | . . 3 ⊢ (𝜓 ↔ 𝜒) | |
| 3 | 2 | bicomi 224 | . 2 ⊢ (𝜒 ↔ 𝜓) |
| 4 | 1, 3 | bitr2di 288 | 1 ⊢ (𝜑 → (𝜓 ↔ 𝜃)) |
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