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Theorem rexbii2 2383
Description: Inference adding different restricted existential quantifiers to each side of an equivalence. (Contributed by NM, 4-Feb-2004.)
Hypothesis
Ref Expression
rexbii2.1 ((𝑥𝐴𝜑) ↔ (𝑥𝐵𝜓))
Assertion
Ref Expression
rexbii2 (∃𝑥𝐴 𝜑 ↔ ∃𝑥𝐵 𝜓)

Proof of Theorem rexbii2
StepHypRef Expression
1 rexbii2.1 . . 3 ((𝑥𝐴𝜑) ↔ (𝑥𝐵𝜓))
21exbii 1537 . 2 (∃𝑥(𝑥𝐴𝜑) ↔ ∃𝑥(𝑥𝐵𝜓))
3 df-rex 2359 . 2 (∃𝑥𝐴 𝜑 ↔ ∃𝑥(𝑥𝐴𝜑))
4 df-rex 2359 . 2 (∃𝑥𝐵 𝜓 ↔ ∃𝑥(𝑥𝐵𝜓))
52, 3, 43bitr4i 210 1 (∃𝑥𝐴 𝜑 ↔ ∃𝑥𝐵 𝜓)
Colors of variables: wff set class
Syntax hints:  wa 102  wb 103  wex 1422  wcel 1434  wrex 2354
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-5 1377  ax-gen 1379  ax-ie1 1423  ax-ie2 1424  ax-4 1441  ax-ial 1468
This theorem depends on definitions:  df-bi 115  df-rex 2359
This theorem is referenced by:  rexeqbii  2385  rexbiia  2387  rexrab  2766  rexdifsn  3546  bnd2  3973  rexuz2  8964  rexrp  9051  rexuz3  10250
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