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Theorem rexanid 3251
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 531 . . 3 (𝑥𝐴 → (𝜑 ↔ (𝑥𝐴𝜑)))
21bicomd 225 . 2 (𝑥𝐴 → ((𝑥𝐴𝜑) ↔ 𝜑))
32rexbiia 3245 1 (∃𝑥𝐴 (𝑥𝐴𝜑) ↔ ∃𝑥𝐴 𝜑)
Colors of variables: wff setvar class
Syntax hints:  wb 208  wa 398  wcel 2113  wrex 3138
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809
This theorem depends on definitions:  df-bi 209  df-an 399  df-ex 1780  df-rex 3143
This theorem is referenced by:  sn-axrep5v  39184
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