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Related theorems GIF version |
| Description: An inference from a nested biconditional, related to modus ponens. |
| Ref | Expression |
|---|---|
| mpbii.min | ⊢ ψ |
| mpbii.maj | ⊢ (φ → (ψ ↔ χ)) |
| Ref | Expression |
|---|---|
| mpbii | ⊢ (φ → χ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | mpbii.min | . 2 ⊢ ψ | |
| 2 | mpbii.maj | . . 3 ⊢ (φ → (ψ ↔ χ)) | |
| 3 | 2 | biimpd 153 | . 2 ⊢ (φ → (ψ → χ)) |
| 4 | 1, 3 | mpi 44 | 1 ⊢ (φ → χ) |