Description: Given a, a implies it is not the case a implies a self contradiction. (Contributed by Jarvin Udandy, 7-Sep-2020)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | ainaiaandna.1 | ⊢ 𝜑 | |
| Assertion | ainaiaandna | ⊢ ( 𝜑 → ¬ ( 𝜑 → ( 𝜑 ∧ ¬ 𝜑 ) ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | ainaiaandna.1 | ⊢ 𝜑 | |
| 2 | 1 | atnaiana | ⊢ ¬ ( 𝜑 → ( 𝜑 ∧ ¬ 𝜑 ) ) | 
| 3 | 2 | a1i | ⊢ ( 𝜑 → ¬ ( 𝜑 → ( 𝜑 ∧ ¬ 𝜑 ) ) ) |