Theorem bj-nnfe 37047

Description: Nonfreeness implies the equivalent of ax5e 1914. (Contributed by BJ, 28-Jul-2023.)

Assertion

Ref	Expression
bj-nnfe	⊢ (Ⅎ'𝑥𝜑 → (∃𝑥𝜑 → 𝜑))

Proof of Theorem bj-nnfe

Step	Hyp	Ref	Expression
1		df-bj-nnf 37043	. 2 ⊢ (Ⅎ'𝑥𝜑 ↔ ((∃𝑥𝜑 → 𝜑) ∧ (𝜑 → ∀𝑥𝜑)))
2	1	simplbi 496	1 ⊢ (Ⅎ'𝑥𝜑 → (∃𝑥𝜑 → 𝜑))

Syntax hints:   → wi 4  ∀wal 1540  ∃wex 1781  Ⅎ'wnnf 37042

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 207  df-an 396  df-bj-nnf 37043

This theorem is referenced by:  bj-nnfed  37048  bj-nnfei  37049  bj-nnfea  37050  bj-nnfim1  37057  bj-nnfim2  37058  bj-nnf-exlim  37076  bj-19.21t  37077  bj-19.36im  37079  bj-19.42t  37081  bj-sbft  37094