Theorem intnand 882

Description: Introduction of conjunct inside of a contradiction. (Contributed by NM, 10-Jul-2005.)

Hypothesis

Ref	Expression
intnand.1	⊢ (φ → ¬ ψ)

Assertion

Ref	Expression
intnand	⊢ (φ → ¬ (χ ∧ ψ))

Proof of Theorem intnand

Step	Hyp	Ref	Expression
1		intnand.1	. 2 ⊢ (φ → ¬ ψ)
2		simpr 447	. 2 ⊢ ((χ ∧ ψ) → ψ)
3	1, 2	nsyl 113	1 ⊢ (φ → ¬ (χ ∧ ψ))

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 358

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 177  df-an 360

This theorem is referenced by:  nnadjoinpw  4521  nmembers1lem3  6270