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Theorem ralrals 17057
Description: If the universal part of a restricted "all some" statement holds, then the statement reduces to the existence of a member of 𝐴 satisfying its antecedent. This is the restricted counterpart of ralals 17063. (Contributed by Peter Mazsa and David A. Wheeler, 20-Jul-2026.)
Assertion
Ref Expression
ralrals (∀𝑥𝐴 (𝜑𝜓) → (∀∃𝑥𝐴(𝜑𝜓) ↔ ∃𝑥𝐴 𝜑))

Proof of Theorem ralrals
StepHypRef Expression
1 df-rals 17037 . 2 (∀∃𝑥𝐴(𝜑𝜓) ↔ (∀𝑥𝐴 (𝜑𝜓) ∧ ∃𝑥𝐴 𝜑))
2 ibar 301 . . 3 (∀𝑥𝐴 (𝜑𝜓) → (∃𝑥𝐴 𝜑 ↔ (∀𝑥𝐴 (𝜑𝜓) ∧ ∃𝑥𝐴 𝜑)))
32bicomd 141 . 2 (∀𝑥𝐴 (𝜑𝜓) → ((∀𝑥𝐴 (𝜑𝜓) ∧ ∃𝑥𝐴 𝜑) ↔ ∃𝑥𝐴 𝜑))
41, 3bitrid 192 1 (∀𝑥𝐴 (𝜑𝜓) → (∀∃𝑥𝐴(𝜑𝜓) ↔ ∃𝑥𝐴 𝜑))
Colors of variables: wff set class
Syntax hints:  wi 4  wa 104  wb 105  wral 2528  wrex 2529  ∀∃wrals 17035
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108
This theorem depends on definitions:  df-bi 117  df-rals 17037
This theorem is referenced by: (None)
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