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Related theorems GIF version |
| Description: Inference derived from axiom ax-1 3. See a1d 14 for an explanation of our informal use of the terms "inference" and "deduction". |
| Ref | Expression |
|---|---|
| a1i.1 | ⊢ φ |
| Ref | Expression |
|---|---|
| a1i | ⊢ (ψ → φ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | a1i.1 | . 2 ⊢ φ | |
| 2 | ax-1 3 | . 2 ⊢ (φ → (ψ → φ)) | |
| 3 | 1, 2 | ax-mp 6 | 1 ⊢ (ψ → φ) |