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Related theorems GIF version |
| Description: Deduction adding a left conjunct to both sides of a logical equivalence. |
| Ref | Expression |
|---|---|
| bid.1 | ⊢ (φ → (ψ ↔ χ)) |
| Ref | Expression |
|---|---|
| anbi2d | ⊢ (φ → ((θ ⋀ ψ) ↔ (θ ⋀ χ))) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | bid.1 | . . . 4 ⊢ (φ → (ψ ↔ χ)) | |
| 2 | 1 | biimpd 153 | . . 3 ⊢ (φ → (ψ → χ)) |
| 3 | 2 | anim2d 564 | . 2 ⊢ (φ → ((θ ⋀ ψ) → (θ ⋀ χ))) |
| 4 | 1 | biimprd 154 | . . 3 ⊢ (φ → (χ → ψ)) |
| 5 | 4 | anim2d 564 | . 2 ⊢ (φ → ((θ ⋀ χ) → (θ ⋀ ψ))) |
| 6 | 3, 5 | impbid 519 | 1 ⊢ (φ → ((θ ⋀ ψ) ↔ (θ ⋀ χ))) |