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Theorem ralsmd 17046
Description: Deduction rule: Given "all some" applied to a class, the class is inhabited. This is stronger than ralsn0d 17045, which only concludes that the class is nonempty; see n0r 3535. (Contributed by David A. Wheeler, 20-Jul-2026.)
Hypothesis
Ref Expression
ralsmd.1 (𝜑 → ∀∃𝑥𝐴(𝜓𝜒))
Assertion
Ref Expression
ralsmd (𝜑 → ∃𝑥 𝑥𝐴)
Distinct variable group:   𝑥,𝐴
Allowed substitution hints:   𝜑(𝑥)   𝜓(𝑥)   𝜒(𝑥)

Proof of Theorem ralsmd
StepHypRef Expression
1 ralsmd.1 . . 3 (𝜑 → ∀∃𝑥𝐴(𝜓𝜒))
21rals2d 17044 . 2 (𝜑 → ∃𝑥𝐴 𝜓)
3 rexm 3627 . 2 (∃𝑥𝐴 𝜓 → ∃𝑥 𝑥𝐴)
42, 3syl 14 1 (𝜑 → ∃𝑥 𝑥𝐴)
Colors of variables: wff set class
Syntax hints:  wi 4  wex 1545  wcel 2209  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  ax-5 1500  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-4 1563  ax-ial 1587
This theorem depends on definitions:  df-bi 117  df-rex 2534  df-rals 17037
This theorem is referenced by: (None)
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