Theorem intnanr

Description: Introduction of conjunct inside of a contradiction. (Contributed by NM, 3-Apr-1995)

	Ref	Expression
Hypothesis	intnan.1	$$⊢\neg \phi$$
Assertion	intnanr	$$⊢\neg \left(\phi \wedge \psi \right)$$

Proof

Step	Hyp	Ref	Expression
1		intnan.1	$$⊢\neg \phi$$
2		simpl	$$⊢\left(\phi \wedge \psi \right)\to \phi$$
3	1 2	mto	$$⊢\neg \left(\phi \wedge \psi \right)$$