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Metamath Proof Explorer

Theorem bj-nexrt

Description: Closed form of nexr . Contrapositive of 19.8a . (Contributed by BJ, 20-Oct-2019)

Ref Expression
Assertion bj-nexrt ( ¬ ∃ 𝑥 𝜑 → ¬ 𝜑 )

Proof

Step Hyp Ref Expression
1 19.8a ⊢ ( 𝜑 → ∃ 𝑥 𝜑 )
2 1 con3i ⊢ ( ¬ ∃ 𝑥 𝜑 → ¬ 𝜑 )