Description: Given a, it is not the case a implies a self contradiction. (Contributed by Jarvin Udandy, 7-Sep-2020)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | atnaiana.1 | ⊢ 𝜑 | |
| Assertion | atnaiana | ⊢ ¬ ( 𝜑 → ( 𝜑 ∧ ¬ 𝜑 ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | atnaiana.1 | ⊢ 𝜑 | |
| 2 | 1 | bitru | ⊢ ( 𝜑 ↔ ⊤ ) | 
| 3 | pm3.24 | ⊢ ¬ ( 𝜑 ∧ ¬ 𝜑 ) | |
| 4 | 3 | bifal | ⊢ ( ( 𝜑 ∧ ¬ 𝜑 ) ↔ ⊥ ) | 
| 5 | 2 4 | aifftbifffaibif | ⊢ ( ( 𝜑 → ( 𝜑 ∧ ¬ 𝜑 ) ) ↔ ⊥ ) | 
| 6 | 5 | aisfina | ⊢ ¬ ( 𝜑 → ( 𝜑 ∧ ¬ 𝜑 ) ) |