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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 → ∃ 𝑥 𝜓 )
Assertion bnj937 ( 𝜑 → 𝜓 )

Proof

Step Hyp Ref Expression
1 bnj937.1 ⊢ ( 𝜑 → ∃ 𝑥 𝜓 )
2 19.9v ⊢ ( ∃ 𝑥 𝜓 ↔ 𝜓 )
3 1 2 sylib ⊢ ( 𝜑 → 𝜓 )