Theorem nfntht 1797

Description: Closed form of nfnth 1806. (Contributed by BJ, 16-Sep-2021.) (Proof shortened by Wolf Lammen, 4-Sep-2022.)

Assertion

Ref	Expression
nfntht	⊢ (¬ ∃𝑥𝜑 → Ⅎ𝑥𝜑)

Proof of Theorem nfntht

Step	Hyp	Ref	Expression
1		pm2.21 123	. 2 ⊢ (¬ ∃𝑥𝜑 → (∃𝑥𝜑 → ∀𝑥𝜑))
2	1	nfd 1794	1 ⊢ (¬ ∃𝑥𝜑 → Ⅎ𝑥𝜑)

Syntax hints:  ¬ wn 3   → wi 4  ∀wal 1537  ∃wex 1783  Ⅎwnf 1787

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 206  df-nf 1788

This theorem is referenced by:  nfntht2  1798