Theorem intn3an1d

Description: Introduction of a triple conjunct inside a contradiction. (Contributed by FL, 27-Dec-2007) (Proof shortened by Andrew Salmon, 26-Jun-2011)

	Ref	Expression
Hypothesis	intn3and.1	⊢ ( 𝜑 → ¬ 𝜓 )
Assertion	intn3an1d	⊢ ( 𝜑 → ¬ ( 𝜓 ∧ 𝜒 ∧ 𝜃 ) )

Proof

Step	Hyp	Ref	Expression
1		intn3and.1	⊢ ( 𝜑 → ¬ 𝜓 )
2		simp1	⊢ ( ( 𝜓 ∧ 𝜒 ∧ 𝜃 ) → 𝜓 )
3	1 2	nsyl	⊢ ( 𝜑 → ¬ ( 𝜓 ∧ 𝜒 ∧ 𝜃 ) )