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Theorem rexanid 3175
Description: Cancellation law for restricted existential quantification. (Contributed by Peter Mazsa, 24-May-2018.) (Proof shortened by Wolf Lammen, 8-Jul-2023.)
Assertion
Ref Expression
rexanid (∃𝑥𝐴 (𝑥𝐴𝜑) ↔ ∃𝑥𝐴 𝜑)

Proof of Theorem rexanid
StepHypRef Expression
1 ibar 532 . . 3 (𝑥𝐴 → (𝜑 ↔ (𝑥𝐴𝜑)))
21bicomd 226 . 2 (𝑥𝐴 → ((𝑥𝐴𝜑) ↔ 𝜑))
32rexbiia 3169 1 (∃𝑥𝐴 (𝑥𝐴𝜑) ↔ ∃𝑥𝐴 𝜑)
Colors of variables: wff setvar class
Syntax hints:  wb 209  wa 399  wcel 2110  wrex 3062
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1803  ax-4 1817
This theorem depends on definitions:  df-bi 210  df-an 400  df-ex 1788  df-rex 3067
This theorem is referenced by:  sn-axrep5v  39907
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