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Metamath Proof Explorer

Theorem bnj937

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

		Ref	Expression
	Hypothesis	bnj937.1	$⊢ φ \to \exists x ψ$
	Assertion	bnj937	$⊢ φ \to ψ$

Step	Hyp	Ref	Expression
1		bnj937.1	$⊢ φ \to \exists x ψ$
2		19.9v	$⊢ \exists x ψ \leftrightarrow ψ$
3	1 2	sylib	$⊢ φ \to ψ$