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Theorem rexxpf 4446
Description: Version of rexxp 4443 with bound-variable hypotheses. (Contributed by NM, 19-Dec-2008.) (Revised by Mario Carneiro, 15-Oct-2016.)
Hypotheses
Ref Expression
ralxpf.1 𝑦𝜑
ralxpf.2 𝑧𝜑
ralxpf.3 𝑥𝜓
ralxpf.4 (𝑥 = ⟨𝑦, 𝑧⟩ → (𝜑𝜓))
Assertion
Ref Expression
rexxpf (∃𝑥 ∈ (𝐴 × 𝐵)𝜑 ↔ ∃𝑦𝐴𝑧𝐵 𝜓)
Distinct variable groups:   𝑥,𝑦,𝐴   𝑥,𝑧,𝐵,𝑦
Allowed substitution hints:   𝜑(𝑥,𝑦,𝑧)   𝜓(𝑥,𝑦,𝑧)   𝐴(𝑧)

Proof of Theorem rexxpf
Dummy variables 𝑣 𝑢 𝑤 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 cbvrexsv 2542 . 2 (∃𝑥 ∈ (𝐴 × 𝐵)𝜑 ↔ ∃𝑣 ∈ (𝐴 × 𝐵)[𝑣 / 𝑥]𝜑)
2 cbvrexsv 2542 . . . 4 (∃𝑧𝐵 [𝑤 / 𝑦]𝜓 ↔ ∃𝑢𝐵 [𝑢 / 𝑧][𝑤 / 𝑦]𝜓)
32rexbii 2328 . . 3 (∃𝑤𝐴𝑧𝐵 [𝑤 / 𝑦]𝜓 ↔ ∃𝑤𝐴𝑢𝐵 [𝑢 / 𝑧][𝑤 / 𝑦]𝜓)
4 nfv 1421 . . . 4 𝑤𝑧𝐵 𝜓
5 nfcv 2178 . . . . 5 𝑦𝐵
6 nfs1v 1815 . . . . 5 𝑦[𝑤 / 𝑦]𝜓
75, 6nfrexxy 2358 . . . 4 𝑦𝑧𝐵 [𝑤 / 𝑦]𝜓
8 sbequ12 1654 . . . . 5 (𝑦 = 𝑤 → (𝜓 ↔ [𝑤 / 𝑦]𝜓))
98rexbidv 2324 . . . 4 (𝑦 = 𝑤 → (∃𝑧𝐵 𝜓 ↔ ∃𝑧𝐵 [𝑤 / 𝑦]𝜓))
104, 7, 9cbvrex 2527 . . 3 (∃𝑦𝐴𝑧𝐵 𝜓 ↔ ∃𝑤𝐴𝑧𝐵 [𝑤 / 𝑦]𝜓)
11 vex 2557 . . . . . 6 𝑤 ∈ V
12 vex 2557 . . . . . 6 𝑢 ∈ V
1311, 12eqvinop 3977 . . . . 5 (𝑣 = ⟨𝑤, 𝑢⟩ ↔ ∃𝑦𝑧(𝑣 = ⟨𝑦, 𝑧⟩ ∧ ⟨𝑦, 𝑧⟩ = ⟨𝑤, 𝑢⟩))
14 ralxpf.1 . . . . . . . 8 𝑦𝜑
1514nfsb 1822 . . . . . . 7 𝑦[𝑣 / 𝑥]𝜑
166nfsb 1822 . . . . . . 7 𝑦[𝑢 / 𝑧][𝑤 / 𝑦]𝜓
1715, 16nfbi 1481 . . . . . 6 𝑦([𝑣 / 𝑥]𝜑 ↔ [𝑢 / 𝑧][𝑤 / 𝑦]𝜓)
18 ralxpf.2 . . . . . . . . 9 𝑧𝜑
1918nfsb 1822 . . . . . . . 8 𝑧[𝑣 / 𝑥]𝜑
20 nfs1v 1815 . . . . . . . 8 𝑧[𝑢 / 𝑧][𝑤 / 𝑦]𝜓
2119, 20nfbi 1481 . . . . . . 7 𝑧([𝑣 / 𝑥]𝜑 ↔ [𝑢 / 𝑧][𝑤 / 𝑦]𝜓)
22 ralxpf.3 . . . . . . . . 9 𝑥𝜓
23 ralxpf.4 . . . . . . . . 9 (𝑥 = ⟨𝑦, 𝑧⟩ → (𝜑𝜓))
2422, 23sbhypf 2600 . . . . . . . 8 (𝑣 = ⟨𝑦, 𝑧⟩ → ([𝑣 / 𝑥]𝜑𝜓))
25 vex 2557 . . . . . . . . . 10 𝑦 ∈ V
26 vex 2557 . . . . . . . . . 10 𝑧 ∈ V
2725, 26opth 3971 . . . . . . . . 9 (⟨𝑦, 𝑧⟩ = ⟨𝑤, 𝑢⟩ ↔ (𝑦 = 𝑤𝑧 = 𝑢))
28 sbequ12 1654 . . . . . . . . . 10 (𝑧 = 𝑢 → ([𝑤 / 𝑦]𝜓 ↔ [𝑢 / 𝑧][𝑤 / 𝑦]𝜓))
298, 28sylan9bb 435 . . . . . . . . 9 ((𝑦 = 𝑤𝑧 = 𝑢) → (𝜓 ↔ [𝑢 / 𝑧][𝑤 / 𝑦]𝜓))
3027, 29sylbi 114 . . . . . . . 8 (⟨𝑦, 𝑧⟩ = ⟨𝑤, 𝑢⟩ → (𝜓 ↔ [𝑢 / 𝑧][𝑤 / 𝑦]𝜓))
3124, 30sylan9bb 435 . . . . . . 7 ((𝑣 = ⟨𝑦, 𝑧⟩ ∧ ⟨𝑦, 𝑧⟩ = ⟨𝑤, 𝑢⟩) → ([𝑣 / 𝑥]𝜑 ↔ [𝑢 / 𝑧][𝑤 / 𝑦]𝜓))
3221, 31exlimi 1485 . . . . . 6 (∃𝑧(𝑣 = ⟨𝑦, 𝑧⟩ ∧ ⟨𝑦, 𝑧⟩ = ⟨𝑤, 𝑢⟩) → ([𝑣 / 𝑥]𝜑 ↔ [𝑢 / 𝑧][𝑤 / 𝑦]𝜓))
3317, 32exlimi 1485 . . . . 5 (∃𝑦𝑧(𝑣 = ⟨𝑦, 𝑧⟩ ∧ ⟨𝑦, 𝑧⟩ = ⟨𝑤, 𝑢⟩) → ([𝑣 / 𝑥]𝜑 ↔ [𝑢 / 𝑧][𝑤 / 𝑦]𝜓))
3413, 33sylbi 114 . . . 4 (𝑣 = ⟨𝑤, 𝑢⟩ → ([𝑣 / 𝑥]𝜑 ↔ [𝑢 / 𝑧][𝑤 / 𝑦]𝜓))
3534rexxp 4443 . . 3 (∃𝑣 ∈ (𝐴 × 𝐵)[𝑣 / 𝑥]𝜑 ↔ ∃𝑤𝐴𝑢𝐵 [𝑢 / 𝑧][𝑤 / 𝑦]𝜓)
363, 10, 353bitr4ri 202 . 2 (∃𝑣 ∈ (𝐴 × 𝐵)[𝑣 / 𝑥]𝜑 ↔ ∃𝑦𝐴𝑧𝐵 𝜓)
371, 36bitri 173 1 (∃𝑥 ∈ (𝐴 × 𝐵)𝜑 ↔ ∃𝑦𝐴𝑧𝐵 𝜓)
Colors of variables: wff set class
Syntax hints:  wi 4  wa 97  wb 98   = wceq 1243  wnf 1349  wex 1381  [wsb 1645  wrex 2304  cop 3375   × cxp 4306
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-14 1405  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022  ax-sep 3872  ax-pow 3924  ax-pr 3941
This theorem depends on definitions:  df-bi 110  df-3an 887  df-tru 1246  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-ral 2308  df-rex 2309  df-v 2556  df-sbc 2762  df-csb 2850  df-un 2919  df-in 2921  df-ss 2928  df-pw 3358  df-sn 3378  df-pr 3379  df-op 3381  df-iun 3656  df-opab 3816  df-xp 4314  df-rel 4315
This theorem is referenced by:  iunxpf  4447
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