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Theorem 19.9OLD 2193
 Description: Obsolete proof of 19.9 2060 as of 6-Oct-2021. (Contributed by FL, 24-Mar-2007.) (Revised by Mario Carneiro, 24-Sep-2016.) (Proof shortened by Wolf Lammen, 30-Dec-2017.) Revised to shorten other proofs. (Revised by Wolf Lammen, 14-Jul-2020.) (Proof modification is discouraged.) (New usage is discouraged.)
Hypothesis
Ref Expression
19.9OLD.1 𝑥𝜑
Assertion
Ref Expression
19.9OLD (∃𝑥𝜑𝜑)

Proof of Theorem 19.9OLD
StepHypRef Expression
1 19.9OLD.1 . 2 𝑥𝜑
2 19.9tOLD 2192 . 2 (Ⅎ𝑥𝜑 → (∃𝑥𝜑𝜑))
31, 2ax-mp 5 1 (∃𝑥𝜑𝜑)
 Colors of variables: wff setvar class Syntax hints:   ↔ wb 195  ∃wex 1695  ℲwnfOLD 1700 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-10 2006  ax-12 2034 This theorem depends on definitions:  df-bi 196  df-ex 1696  df-nfOLD 1712 This theorem is referenced by:  19.9hOLD  2194  exlimdOLD  2211
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