Metamath Proof Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > MPE Home > Th. List > mtod | Structured version Visualization version GIF version |
Description: Modus tollens deduction. (Contributed by NM, 3-Apr-1994.) (Proof shortened by Wolf Lammen, 11-Sep-2013.) |
Ref | Expression |
---|---|
mtod.1 | ⊢ (𝜑 → ¬ 𝜒) |
mtod.2 | ⊢ (𝜑 → (𝜓 → 𝜒)) |
Ref | Expression |
---|---|
mtod | ⊢ (𝜑 → ¬ 𝜓) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mtod.2 | . 2 ⊢ (𝜑 → (𝜓 → 𝜒)) | |
2 | mtod.1 | . . 3 ⊢ (𝜑 → ¬ 𝜒) | |
3 | 2 | a1d 25 | . 2 ⊢ (𝜑 → (𝜓 → ¬ 𝜒)) |
4 | 1, 3 | pm2.65d 195 | 1 ⊢ (𝜑 → ¬ 𝜓) |
Copyright terms: Public domain | W3C validator |