Theorem bnj1232

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

	Ref	Expression
Hypothesis	bnj1232.1	$$⊢\phi \leftrightarrow \left(\psi \wedge \chi \wedge \theta \wedge \tau \right)$$
Assertion	bnj1232	$$⊢\phi \to \psi$$

Proof

Step	Hyp	Ref	Expression
1		bnj1232.1	$$⊢\phi \leftrightarrow \left(\psi \wedge \chi \wedge \theta \wedge \tau \right)$$
2		bnj642	$$⊢\left(\psi \wedge \chi \wedge \theta \wedge \tau \right)\to \psi$$
3	1 2	sylbi	$$⊢\phi \to \psi$$