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Theorem reusv3 4349
Description: Two ways to express single-valuedness of a class expression 𝐶(𝑦). See reusv1 4347 for the connection to uniqueness. (Contributed by NM, 27-Dec-2012.)
Hypotheses
Ref Expression
reusv3.1 (𝑦 = 𝑧 → (𝜑𝜓))
reusv3.2 (𝑦 = 𝑧𝐶 = 𝐷)
Assertion
Ref Expression
reusv3 (∃𝑦𝐵 (𝜑𝐶𝐴) → (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) ↔ ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶)))
Distinct variable groups:   𝑥,𝑦,𝑧,𝐵   𝑥,𝐶,𝑧   𝑥,𝐷,𝑦   𝜑,𝑥,𝑧   𝜓,𝑥,𝑦   𝑥,𝐴,𝑦,𝑧
Allowed substitution hints:   𝜑(𝑦)   𝜓(𝑧)   𝐶(𝑦)   𝐷(𝑧)

Proof of Theorem reusv3
StepHypRef Expression
1 reusv3.1 . . . . 5 (𝑦 = 𝑧 → (𝜑𝜓))
2 reusv3.2 . . . . . 6 (𝑦 = 𝑧𝐶 = 𝐷)
32eleq1d 2184 . . . . 5 (𝑦 = 𝑧 → (𝐶𝐴𝐷𝐴))
41, 3anbi12d 462 . . . 4 (𝑦 = 𝑧 → ((𝜑𝐶𝐴) ↔ (𝜓𝐷𝐴)))
54cbvrexv 2630 . . 3 (∃𝑦𝐵 (𝜑𝐶𝐴) ↔ ∃𝑧𝐵 (𝜓𝐷𝐴))
6 nfra2xy 2450 . . . . 5 𝑧𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷)
7 nfv 1491 . . . . 5 𝑧𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶)
86, 7nfim 1534 . . . 4 𝑧(∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) → ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶))
9 risset 2438 . . . . . 6 (𝐷𝐴 ↔ ∃𝑥𝐴 𝑥 = 𝐷)
10 ralcom 2569 . . . . . . . . . . . . . 14 (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) ↔ ∀𝑧𝐵𝑦𝐵 ((𝜑𝜓) → 𝐶 = 𝐷))
11 impexp 261 . . . . . . . . . . . . . . . . . 18 (((𝜑𝜓) → 𝐶 = 𝐷) ↔ (𝜑 → (𝜓𝐶 = 𝐷)))
12 bi2.04 247 . . . . . . . . . . . . . . . . . 18 ((𝜑 → (𝜓𝐶 = 𝐷)) ↔ (𝜓 → (𝜑𝐶 = 𝐷)))
1311, 12bitri 183 . . . . . . . . . . . . . . . . 17 (((𝜑𝜓) → 𝐶 = 𝐷) ↔ (𝜓 → (𝜑𝐶 = 𝐷)))
1413ralbii 2416 . . . . . . . . . . . . . . . 16 (∀𝑦𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) ↔ ∀𝑦𝐵 (𝜓 → (𝜑𝐶 = 𝐷)))
15 r19.21v 2484 . . . . . . . . . . . . . . . 16 (∀𝑦𝐵 (𝜓 → (𝜑𝐶 = 𝐷)) ↔ (𝜓 → ∀𝑦𝐵 (𝜑𝐶 = 𝐷)))
1614, 15bitri 183 . . . . . . . . . . . . . . 15 (∀𝑦𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) ↔ (𝜓 → ∀𝑦𝐵 (𝜑𝐶 = 𝐷)))
1716ralbii 2416 . . . . . . . . . . . . . 14 (∀𝑧𝐵𝑦𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) ↔ ∀𝑧𝐵 (𝜓 → ∀𝑦𝐵 (𝜑𝐶 = 𝐷)))
1810, 17bitri 183 . . . . . . . . . . . . 13 (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) ↔ ∀𝑧𝐵 (𝜓 → ∀𝑦𝐵 (𝜑𝐶 = 𝐷)))
19 rsp 2455 . . . . . . . . . . . . 13 (∀𝑧𝐵 (𝜓 → ∀𝑦𝐵 (𝜑𝐶 = 𝐷)) → (𝑧𝐵 → (𝜓 → ∀𝑦𝐵 (𝜑𝐶 = 𝐷))))
2018, 19sylbi 120 . . . . . . . . . . . 12 (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) → (𝑧𝐵 → (𝜓 → ∀𝑦𝐵 (𝜑𝐶 = 𝐷))))
2120com3l 81 . . . . . . . . . . 11 (𝑧𝐵 → (𝜓 → (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) → ∀𝑦𝐵 (𝜑𝐶 = 𝐷))))
2221imp31 254 . . . . . . . . . 10 (((𝑧𝐵𝜓) ∧ ∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷)) → ∀𝑦𝐵 (𝜑𝐶 = 𝐷))
23 eqeq1 2122 . . . . . . . . . . . . 13 (𝑥 = 𝐷 → (𝑥 = 𝐶𝐷 = 𝐶))
24 eqcom 2117 . . . . . . . . . . . . 13 (𝐷 = 𝐶𝐶 = 𝐷)
2523, 24syl6bb 195 . . . . . . . . . . . 12 (𝑥 = 𝐷 → (𝑥 = 𝐶𝐶 = 𝐷))
2625imbi2d 229 . . . . . . . . . . 11 (𝑥 = 𝐷 → ((𝜑𝑥 = 𝐶) ↔ (𝜑𝐶 = 𝐷)))
2726ralbidv 2412 . . . . . . . . . 10 (𝑥 = 𝐷 → (∀𝑦𝐵 (𝜑𝑥 = 𝐶) ↔ ∀𝑦𝐵 (𝜑𝐶 = 𝐷)))
2822, 27syl5ibrcom 156 . . . . . . . . 9 (((𝑧𝐵𝜓) ∧ ∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷)) → (𝑥 = 𝐷 → ∀𝑦𝐵 (𝜑𝑥 = 𝐶)))
2928reximdv 2508 . . . . . . . 8 (((𝑧𝐵𝜓) ∧ ∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷)) → (∃𝑥𝐴 𝑥 = 𝐷 → ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶)))
3029ex 114 . . . . . . 7 ((𝑧𝐵𝜓) → (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) → (∃𝑥𝐴 𝑥 = 𝐷 → ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶))))
3130com23 78 . . . . . 6 ((𝑧𝐵𝜓) → (∃𝑥𝐴 𝑥 = 𝐷 → (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) → ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶))))
329, 31syl5bi 151 . . . . 5 ((𝑧𝐵𝜓) → (𝐷𝐴 → (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) → ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶))))
3332expimpd 358 . . . 4 (𝑧𝐵 → ((𝜓𝐷𝐴) → (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) → ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶))))
348, 33rexlimi 2517 . . 3 (∃𝑧𝐵 (𝜓𝐷𝐴) → (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) → ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶)))
355, 34sylbi 120 . 2 (∃𝑦𝐵 (𝜑𝐶𝐴) → (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) → ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶)))
361, 2reusv3i 4348 . 2 (∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶) → ∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷))
3735, 36impbid1 141 1 (∃𝑦𝐵 (𝜑𝐶𝐴) → (∀𝑦𝐵𝑧𝐵 ((𝜑𝜓) → 𝐶 = 𝐷) ↔ ∃𝑥𝐴𝑦𝐵 (𝜑𝑥 = 𝐶)))
Colors of variables: wff set class
Syntax hints:  wi 4  wa 103  wb 104   = wceq 1314  wcel 1463  wral 2391  wrex 2392
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 681  ax-5 1406  ax-7 1407  ax-gen 1408  ax-ie1 1452  ax-ie2 1453  ax-8 1465  ax-10 1466  ax-11 1467  ax-i12 1468  ax-bndl 1469  ax-4 1470  ax-17 1489  ax-i9 1493  ax-ial 1497  ax-i5r 1498  ax-ext 2097
This theorem depends on definitions:  df-bi 116  df-tru 1317  df-nf 1420  df-sb 1719  df-cleq 2108  df-clel 2111  df-nfc 2245  df-ral 2396  df-rex 2397
This theorem is referenced by: (None)
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