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Theorem ralxfr2d 4242
 Description: Transfer universal quantification from a variable 𝑥 to another variable 𝑦 contained in expression 𝐴. (Contributed by Mario Carneiro, 20-Aug-2014.)
Hypotheses
Ref Expression
ralxfr2d.1 ((𝜑𝑦𝐶) → 𝐴𝑉)
ralxfr2d.2 (𝜑 → (𝑥𝐵 ↔ ∃𝑦𝐶 𝑥 = 𝐴))
ralxfr2d.3 ((𝜑𝑥 = 𝐴) → (𝜓𝜒))
Assertion
Ref Expression
ralxfr2d (𝜑 → (∀𝑥𝐵 𝜓 ↔ ∀𝑦𝐶 𝜒))
Distinct variable groups:   𝑥,𝐴   𝑥,𝑦,𝐵   𝑥,𝐶   𝜒,𝑥   𝜑,𝑥,𝑦   𝜓,𝑦
Allowed substitution hints:   𝜓(𝑥)   𝜒(𝑦)   𝐴(𝑦)   𝐶(𝑦)   𝑉(𝑥,𝑦)

Proof of Theorem ralxfr2d
StepHypRef Expression
1 ralxfr2d.1 . . . 4 ((𝜑𝑦𝐶) → 𝐴𝑉)
2 elisset 2622 . . . 4 (𝐴𝑉 → ∃𝑥 𝑥 = 𝐴)
31, 2syl 14 . . 3 ((𝜑𝑦𝐶) → ∃𝑥 𝑥 = 𝐴)
4 ralxfr2d.2 . . . . . . . 8 (𝜑 → (𝑥𝐵 ↔ ∃𝑦𝐶 𝑥 = 𝐴))
54biimprd 156 . . . . . . 7 (𝜑 → (∃𝑦𝐶 𝑥 = 𝐴𝑥𝐵))
6 r19.23v 2474 . . . . . . 7 (∀𝑦𝐶 (𝑥 = 𝐴𝑥𝐵) ↔ (∃𝑦𝐶 𝑥 = 𝐴𝑥𝐵))
75, 6sylibr 132 . . . . . 6 (𝜑 → ∀𝑦𝐶 (𝑥 = 𝐴𝑥𝐵))
87r19.21bi 2454 . . . . 5 ((𝜑𝑦𝐶) → (𝑥 = 𝐴𝑥𝐵))
9 eleq1 2145 . . . . 5 (𝑥 = 𝐴 → (𝑥𝐵𝐴𝐵))
108, 9mpbidi 149 . . . 4 ((𝜑𝑦𝐶) → (𝑥 = 𝐴𝐴𝐵))
1110exlimdv 1742 . . 3 ((𝜑𝑦𝐶) → (∃𝑥 𝑥 = 𝐴𝐴𝐵))
123, 11mpd 13 . 2 ((𝜑𝑦𝐶) → 𝐴𝐵)
134biimpa 290 . 2 ((𝜑𝑥𝐵) → ∃𝑦𝐶 𝑥 = 𝐴)
14 ralxfr2d.3 . 2 ((𝜑𝑥 = 𝐴) → (𝜓𝜒))
1512, 13, 14ralxfrd 4240 1 (𝜑 → (∀𝑥𝐵 𝜓 ↔ ∀𝑦𝐶 𝜒))
 Colors of variables: wff set class Syntax hints:   → wi 4   ∧ wa 102   ↔ wb 103   = wceq 1285  ∃wex 1422   ∈ wcel 1434  ∀wral 2353  ∃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-io 663  ax-5 1377  ax-7 1378  ax-gen 1379  ax-ie1 1423  ax-ie2 1424  ax-8 1436  ax-10 1437  ax-11 1438  ax-i12 1439  ax-bndl 1440  ax-4 1441  ax-17 1460  ax-i9 1464  ax-ial 1468  ax-i5r 1469  ax-ext 2065 This theorem depends on definitions:  df-bi 115  df-tru 1288  df-nf 1391  df-sb 1688  df-clab 2070  df-cleq 2076  df-clel 2079  df-nfc 2212  df-ral 2358  df-rex 2359  df-v 2612 This theorem is referenced by:  ralrn  5358  ralima  5448
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