Metamath Proof Explorer

Theorem bnj721

Description: /\ -manipulation. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

		Ref	Expression
	Hypothesis	bnj721.1	$⊢ (φ \land ψ \land χ) \to τ$
	Assertion	bnj721	$⊢ (φ \land ψ \land χ \land θ) \to τ$

Step	Hyp	Ref	Expression
1		bnj721.1	$⊢ (φ \land ψ \land χ) \to τ$
2		bnj658	$⊢ (φ \land ψ \land χ \land θ) \to (φ \land ψ \land χ)$
3	2 1	syl	$⊢ (φ \land ψ \land χ \land θ) \to τ$