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| Mirrors > Home > ILE Home > Th. List > bitrd | GIF version | ||
| Description: Deduction form of bitri 184. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Wolf Lammen, 14-Apr-2013.) | 
| Ref | Expression | 
|---|---|
| bitrd.1 | ⊢ (𝜑 → (𝜓 ↔ 𝜒)) | 
| bitrd.2 | ⊢ (𝜑 → (𝜒 ↔ 𝜃)) | 
| Ref | Expression | 
|---|---|
| bitrd | ⊢ (𝜑 → (𝜓 ↔ 𝜃)) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | bitrd.1 | . . . 4 ⊢ (𝜑 → (𝜓 ↔ 𝜒)) | |
| 2 | 1 | pm5.74i 180 | . . 3 ⊢ ((𝜑 → 𝜓) ↔ (𝜑 → 𝜒)) | 
| 3 | bitrd.2 | . . . 4 ⊢ (𝜑 → (𝜒 ↔ 𝜃)) | |
| 4 | 3 | pm5.74i 180 | . . 3 ⊢ ((𝜑 → 𝜒) ↔ (𝜑 → 𝜃)) | 
| 5 | 2, 4 | bitri 184 | . 2 ⊢ ((𝜑 → 𝜓) ↔ (𝜑 → 𝜃)) | 
| 6 | 5 | pm5.74ri 181 | 1 ⊢ (𝜑 → (𝜓 ↔ 𝜃)) | 
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