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Theorem rexanid 3116
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 538 . . 3 (𝑥𝐴 → (𝜑 ↔ (𝑥𝐴𝜑)))
21bicomd 226 . 2 (𝑥𝐴 → ((𝑥𝐴𝜑) ↔ 𝜑))
32rexbiia 3112 1 (∃𝑥𝐴 (𝑥𝐴𝜑) ↔ ∃𝑥𝐴 𝜑)
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  wb 209  wa 401  wcel 2146  wrex 3091
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842
This proof depends on definitions:  df-bi 210  df-an 402  df-ex 1813  df-rex 3092
This theorem is used by:  zfrep6  5252  bj-rep  37767  dmqsblocks  39674  sn-axrep5v  43046
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