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Theorem preq12bg 3544
 Description: Closed form of preq12b 3541. (Contributed by Scott Fenton, 28-Mar-2014.)
Assertion
Ref Expression
preq12bg (((𝐴𝑉𝐵𝑊) ∧ (𝐶𝑋𝐷𝑌)) → ({𝐴, 𝐵} = {𝐶, 𝐷} ↔ ((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶))))

Proof of Theorem preq12bg
Dummy variables 𝑥 𝑦 𝑧 𝑤 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 preq1 3447 . . . . . . 7 (𝑥 = 𝐴 → {𝑥, 𝑦} = {𝐴, 𝑦})
21eqeq1d 2048 . . . . . 6 (𝑥 = 𝐴 → ({𝑥, 𝑦} = {𝑧, 𝐷} ↔ {𝐴, 𝑦} = {𝑧, 𝐷}))
3 eqeq1 2046 . . . . . . . 8 (𝑥 = 𝐴 → (𝑥 = 𝑧𝐴 = 𝑧))
43anbi1d 438 . . . . . . 7 (𝑥 = 𝐴 → ((𝑥 = 𝑧𝑦 = 𝐷) ↔ (𝐴 = 𝑧𝑦 = 𝐷)))
5 eqeq1 2046 . . . . . . . 8 (𝑥 = 𝐴 → (𝑥 = 𝐷𝐴 = 𝐷))
65anbi1d 438 . . . . . . 7 (𝑥 = 𝐴 → ((𝑥 = 𝐷𝑦 = 𝑧) ↔ (𝐴 = 𝐷𝑦 = 𝑧)))
74, 6orbi12d 707 . . . . . 6 (𝑥 = 𝐴 → (((𝑥 = 𝑧𝑦 = 𝐷) ∨ (𝑥 = 𝐷𝑦 = 𝑧)) ↔ ((𝐴 = 𝑧𝑦 = 𝐷) ∨ (𝐴 = 𝐷𝑦 = 𝑧))))
82, 7bibi12d 224 . . . . 5 (𝑥 = 𝐴 → (({𝑥, 𝑦} = {𝑧, 𝐷} ↔ ((𝑥 = 𝑧𝑦 = 𝐷) ∨ (𝑥 = 𝐷𝑦 = 𝑧))) ↔ ({𝐴, 𝑦} = {𝑧, 𝐷} ↔ ((𝐴 = 𝑧𝑦 = 𝐷) ∨ (𝐴 = 𝐷𝑦 = 𝑧)))))
98imbi2d 219 . . . 4 (𝑥 = 𝐴 → ((𝐷𝑌 → ({𝑥, 𝑦} = {𝑧, 𝐷} ↔ ((𝑥 = 𝑧𝑦 = 𝐷) ∨ (𝑥 = 𝐷𝑦 = 𝑧)))) ↔ (𝐷𝑌 → ({𝐴, 𝑦} = {𝑧, 𝐷} ↔ ((𝐴 = 𝑧𝑦 = 𝐷) ∨ (𝐴 = 𝐷𝑦 = 𝑧))))))
10 preq2 3448 . . . . . . 7 (𝑦 = 𝐵 → {𝐴, 𝑦} = {𝐴, 𝐵})
1110eqeq1d 2048 . . . . . 6 (𝑦 = 𝐵 → ({𝐴, 𝑦} = {𝑧, 𝐷} ↔ {𝐴, 𝐵} = {𝑧, 𝐷}))
12 eqeq1 2046 . . . . . . . 8 (𝑦 = 𝐵 → (𝑦 = 𝐷𝐵 = 𝐷))
1312anbi2d 437 . . . . . . 7 (𝑦 = 𝐵 → ((𝐴 = 𝑧𝑦 = 𝐷) ↔ (𝐴 = 𝑧𝐵 = 𝐷)))
14 eqeq1 2046 . . . . . . . 8 (𝑦 = 𝐵 → (𝑦 = 𝑧𝐵 = 𝑧))
1514anbi2d 437 . . . . . . 7 (𝑦 = 𝐵 → ((𝐴 = 𝐷𝑦 = 𝑧) ↔ (𝐴 = 𝐷𝐵 = 𝑧)))
1613, 15orbi12d 707 . . . . . 6 (𝑦 = 𝐵 → (((𝐴 = 𝑧𝑦 = 𝐷) ∨ (𝐴 = 𝐷𝑦 = 𝑧)) ↔ ((𝐴 = 𝑧𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝑧))))
1711, 16bibi12d 224 . . . . 5 (𝑦 = 𝐵 → (({𝐴, 𝑦} = {𝑧, 𝐷} ↔ ((𝐴 = 𝑧𝑦 = 𝐷) ∨ (𝐴 = 𝐷𝑦 = 𝑧))) ↔ ({𝐴, 𝐵} = {𝑧, 𝐷} ↔ ((𝐴 = 𝑧𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝑧)))))
1817imbi2d 219 . . . 4 (𝑦 = 𝐵 → ((𝐷𝑌 → ({𝐴, 𝑦} = {𝑧, 𝐷} ↔ ((𝐴 = 𝑧𝑦 = 𝐷) ∨ (𝐴 = 𝐷𝑦 = 𝑧)))) ↔ (𝐷𝑌 → ({𝐴, 𝐵} = {𝑧, 𝐷} ↔ ((𝐴 = 𝑧𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝑧))))))
19 preq1 3447 . . . . . . 7 (𝑧 = 𝐶 → {𝑧, 𝐷} = {𝐶, 𝐷})
2019eqeq2d 2051 . . . . . 6 (𝑧 = 𝐶 → ({𝐴, 𝐵} = {𝑧, 𝐷} ↔ {𝐴, 𝐵} = {𝐶, 𝐷}))
21 eqeq2 2049 . . . . . . . 8 (𝑧 = 𝐶 → (𝐴 = 𝑧𝐴 = 𝐶))
2221anbi1d 438 . . . . . . 7 (𝑧 = 𝐶 → ((𝐴 = 𝑧𝐵 = 𝐷) ↔ (𝐴 = 𝐶𝐵 = 𝐷)))
23 eqeq2 2049 . . . . . . . 8 (𝑧 = 𝐶 → (𝐵 = 𝑧𝐵 = 𝐶))
2423anbi2d 437 . . . . . . 7 (𝑧 = 𝐶 → ((𝐴 = 𝐷𝐵 = 𝑧) ↔ (𝐴 = 𝐷𝐵 = 𝐶)))
2522, 24orbi12d 707 . . . . . 6 (𝑧 = 𝐶 → (((𝐴 = 𝑧𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝑧)) ↔ ((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶))))
2620, 25bibi12d 224 . . . . 5 (𝑧 = 𝐶 → (({𝐴, 𝐵} = {𝑧, 𝐷} ↔ ((𝐴 = 𝑧𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝑧))) ↔ ({𝐴, 𝐵} = {𝐶, 𝐷} ↔ ((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶)))))
2726imbi2d 219 . . . 4 (𝑧 = 𝐶 → ((𝐷𝑌 → ({𝐴, 𝐵} = {𝑧, 𝐷} ↔ ((𝐴 = 𝑧𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝑧)))) ↔ (𝐷𝑌 → ({𝐴, 𝐵} = {𝐶, 𝐷} ↔ ((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶))))))
28 preq2 3448 . . . . . . 7 (𝑤 = 𝐷 → {𝑧, 𝑤} = {𝑧, 𝐷})
2928eqeq2d 2051 . . . . . 6 (𝑤 = 𝐷 → ({𝑥, 𝑦} = {𝑧, 𝑤} ↔ {𝑥, 𝑦} = {𝑧, 𝐷}))
30 eqeq2 2049 . . . . . . . 8 (𝑤 = 𝐷 → (𝑦 = 𝑤𝑦 = 𝐷))
3130anbi2d 437 . . . . . . 7 (𝑤 = 𝐷 → ((𝑥 = 𝑧𝑦 = 𝑤) ↔ (𝑥 = 𝑧𝑦 = 𝐷)))
32 eqeq2 2049 . . . . . . . 8 (𝑤 = 𝐷 → (𝑥 = 𝑤𝑥 = 𝐷))
3332anbi1d 438 . . . . . . 7 (𝑤 = 𝐷 → ((𝑥 = 𝑤𝑦 = 𝑧) ↔ (𝑥 = 𝐷𝑦 = 𝑧)))
3431, 33orbi12d 707 . . . . . 6 (𝑤 = 𝐷 → (((𝑥 = 𝑧𝑦 = 𝑤) ∨ (𝑥 = 𝑤𝑦 = 𝑧)) ↔ ((𝑥 = 𝑧𝑦 = 𝐷) ∨ (𝑥 = 𝐷𝑦 = 𝑧))))
35 vex 2560 . . . . . . 7 𝑥 ∈ V
36 vex 2560 . . . . . . 7 𝑦 ∈ V
37 vex 2560 . . . . . . 7 𝑧 ∈ V
38 vex 2560 . . . . . . 7 𝑤 ∈ V
3935, 36, 37, 38preq12b 3541 . . . . . 6 ({𝑥, 𝑦} = {𝑧, 𝑤} ↔ ((𝑥 = 𝑧𝑦 = 𝑤) ∨ (𝑥 = 𝑤𝑦 = 𝑧)))
4029, 34, 39vtoclbg 2614 . . . . 5 (𝐷𝑌 → ({𝑥, 𝑦} = {𝑧, 𝐷} ↔ ((𝑥 = 𝑧𝑦 = 𝐷) ∨ (𝑥 = 𝐷𝑦 = 𝑧))))
4140a1i 9 . . . 4 ((𝑥𝑉𝑦𝑊𝑧𝑋) → (𝐷𝑌 → ({𝑥, 𝑦} = {𝑧, 𝐷} ↔ ((𝑥 = 𝑧𝑦 = 𝐷) ∨ (𝑥 = 𝐷𝑦 = 𝑧)))))
429, 18, 27, 41vtocl3ga 2623 . . 3 ((𝐴𝑉𝐵𝑊𝐶𝑋) → (𝐷𝑌 → ({𝐴, 𝐵} = {𝐶, 𝐷} ↔ ((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶)))))
43423expa 1104 . 2 (((𝐴𝑉𝐵𝑊) ∧ 𝐶𝑋) → (𝐷𝑌 → ({𝐴, 𝐵} = {𝐶, 𝐷} ↔ ((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶)))))
4443impr 361 1 (((𝐴𝑉𝐵𝑊) ∧ (𝐶𝑋𝐷𝑌)) → ({𝐴, 𝐵} = {𝐶, 𝐷} ↔ ((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶))))
 Colors of variables: wff set class Syntax hints:   → wi 4   ∧ wa 97   ↔ wb 98   ∨ wo 629   ∧ w3a 885   = wceq 1243   ∈ wcel 1393  {cpr 3376 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-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022 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-v 2559  df-un 2922  df-sn 3381  df-pr 3382 This theorem is referenced by:  prneimg  3545
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