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| Mirrors > Home > NFE Home > Th. List > anbi12d | GIF version | ||
| Description: Deduction joining two equivalences to form equivalence of conjunctions. (Contributed by NM, 5-Aug-1993.) |
| Ref | Expression |
|---|---|
| bi12d.1 | ⊢ (φ → (ψ ↔ χ)) |
| bi12d.2 | ⊢ (φ → (θ ↔ τ)) |
| Ref | Expression |
|---|---|
| anbi12d | ⊢ (φ → ((ψ ∧ θ) ↔ (χ ∧ τ))) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | bi12d.1 | . . 3 ⊢ (φ → (ψ ↔ χ)) | |
| 2 | 1 | anbi1d 685 | . 2 ⊢ (φ → ((ψ ∧ θ) ↔ (χ ∧ θ))) |
| 3 | bi12d.2 | . . 3 ⊢ (φ → (θ ↔ τ)) | |
| 4 | 3 | anbi2d 684 | . 2 ⊢ (φ → ((χ ∧ θ) ↔ (χ ∧ τ))) |
| 5 | 2, 4 | bitrd 244 | 1 ⊢ (φ → ((ψ ∧ θ) ↔ (χ ∧ τ))) |
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