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GIF version

Theorem ra4e 1244
Description: Restricted specialization.
Assertion
Ref Expression
ra4e ((xAφ) → ∃xA φ)

Proof of Theorem ra4e
StepHypRef Expression
1 19.8a 712 . 2 ((xAφ) → ∃x(xAφ))
2 df-rex 1206 . 2 (∃xA φ ↔ ∃x(xAφ))
31, 2sylibr 175 1 ((xAφ) → ∃xA φ)
Colors of variables: wff set class
Syntax hints:   → wi 2   ∧ wa 196  ∃wex 678   ∈ wcel 1092  ∃wrex 1202
This theorem is referenced by:  ssiun2 2019  onfr 2237  tfrlem8 2956  tfrlem9 2957  scott0 3542  infxpidmlem7 4939  infxpidmlem8 4940  atom1d 5750
This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6  ax-4 673
This theorem depends on definitions:  df-bi 128  df-ex 679  df-rex 1206
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