Description: Introduction of conjunct inside of a contradiction. (Contributed by NM, 3-Apr-1995)
Ref | Expression | ||
---|---|---|---|
Hypothesis | intnan.1 | ⊢ ¬ 𝜑 | |
Assertion | intnanr | ⊢ ¬ ( 𝜑 ∧ 𝜓 ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | intnan.1 | ⊢ ¬ 𝜑 | |
2 | simpl | ⊢ ( ( 𝜑 ∧ 𝜓 ) → 𝜑 ) | |
3 | 1 2 | mto | ⊢ ¬ ( 𝜑 ∧ 𝜓 ) |