Theorem nnral 2497

Description: The double negation of a universal quantification implies the universal quantification of the double negation. Restricted quantifier version of nnal 1673. (Contributed by Jim Kingdon, 1-Aug-2024.)

Assertion

Ref	Expression
nnral	⊢ (¬ ¬ ∀𝑥 ∈ 𝐴 𝜑 → ∀𝑥 ∈ 𝐴 ¬ ¬ 𝜑)

Proof of Theorem nnral

Step	Hyp	Ref	Expression
1		rexnalim 2496	. . 3 ⊢ (∃𝑥 ∈ 𝐴 ¬ 𝜑 → ¬ ∀𝑥 ∈ 𝐴 𝜑)
2	1	con3i 633	. 2 ⊢ (¬ ¬ ∀𝑥 ∈ 𝐴 𝜑 → ¬ ∃𝑥 ∈ 𝐴 ¬ 𝜑)
3		ralnex 2495	. 2 ⊢ (∀𝑥 ∈ 𝐴 ¬ ¬ 𝜑 ↔ ¬ ∃𝑥 ∈ 𝐴 ¬ 𝜑)
4	2, 3	sylibr 134	1 ⊢ (¬ ¬ ∀𝑥 ∈ 𝐴 𝜑 → ∀𝑥 ∈ 𝐴 ¬ ¬ 𝜑)

Syntax hints:  ¬ wn 3   → wi 4  ∀wral 2485  ∃wrex 2486

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616  ax-5 1471  ax-gen 1473  ax-ie1 1517  ax-ie2 1518  ax-4 1534  ax-17 1550  ax-ial 1558

This theorem depends on definitions:  df-bi 117  df-tru 1376  df-fal 1379  df-nf 1485  df-ral 2490  df-rex 2491

This theorem is referenced by:  onntri13  7363  onntri24  7367