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 ) ) |