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Theorem preleqg 8674
Description: Equality of two unordered pairs when one member of each pair contains the other member. Closed form of preleq 8675. (Contributed by AV, 15-Jun-2022.)
Assertion
Ref Expression
preleqg (((𝐴𝐵𝐵𝑉𝐶𝐷) ∧ {𝐴, 𝐵} = {𝐶, 𝐷}) → (𝐴 = 𝐶𝐵 = 𝐷))

Proof of Theorem preleqg
StepHypRef Expression
1 elneq 8659 . . . . 5 (𝐴𝐵𝐴𝐵)
213ad2ant1 1127 . . . 4 ((𝐴𝐵𝐵𝑉𝐶𝐷) → 𝐴𝐵)
3 preq12nebg 4529 . . . 4 ((𝐴𝐵𝐵𝑉𝐴𝐵) → ({𝐴, 𝐵} = {𝐶, 𝐷} ↔ ((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶))))
42, 3syld3an3 1515 . . 3 ((𝐴𝐵𝐵𝑉𝐶𝐷) → ({𝐴, 𝐵} = {𝐶, 𝐷} ↔ ((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶))))
5 eleq12 2840 . . . . . . . . . 10 ((𝐴 = 𝐷𝐵 = 𝐶) → (𝐴𝐵𝐷𝐶))
6 elnotel 8669 . . . . . . . . . . 11 (𝐷𝐶 → ¬ 𝐶𝐷)
76pm2.21d 119 . . . . . . . . . 10 (𝐷𝐶 → (𝐶𝐷 → (𝐴 = 𝐶𝐵 = 𝐷)))
85, 7syl6bi 243 . . . . . . . . 9 ((𝐴 = 𝐷𝐵 = 𝐶) → (𝐴𝐵 → (𝐶𝐷 → (𝐴 = 𝐶𝐵 = 𝐷))))
98com3l 89 . . . . . . . 8 (𝐴𝐵 → (𝐶𝐷 → ((𝐴 = 𝐷𝐵 = 𝐶) → (𝐴 = 𝐶𝐵 = 𝐷))))
109a1d 25 . . . . . . 7 (𝐴𝐵 → (𝐵𝑉 → (𝐶𝐷 → ((𝐴 = 𝐷𝐵 = 𝐶) → (𝐴 = 𝐶𝐵 = 𝐷)))))
11103imp 1101 . . . . . 6 ((𝐴𝐵𝐵𝑉𝐶𝐷) → ((𝐴 = 𝐷𝐵 = 𝐶) → (𝐴 = 𝐶𝐵 = 𝐷)))
1211com12 32 . . . . 5 ((𝐴 = 𝐷𝐵 = 𝐶) → ((𝐴𝐵𝐵𝑉𝐶𝐷) → (𝐴 = 𝐶𝐵 = 𝐷)))
1312jao1i 845 . . . 4 (((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶)) → ((𝐴𝐵𝐵𝑉𝐶𝐷) → (𝐴 = 𝐶𝐵 = 𝐷)))
1413com12 32 . . 3 ((𝐴𝐵𝐵𝑉𝐶𝐷) → (((𝐴 = 𝐶𝐵 = 𝐷) ∨ (𝐴 = 𝐷𝐵 = 𝐶)) → (𝐴 = 𝐶𝐵 = 𝐷)))
154, 14sylbid 230 . 2 ((𝐴𝐵𝐵𝑉𝐶𝐷) → ({𝐴, 𝐵} = {𝐶, 𝐷} → (𝐴 = 𝐶𝐵 = 𝐷)))
1615imp 393 1 (((𝐴𝐵𝐵𝑉𝐶𝐷) ∧ {𝐴, 𝐵} = {𝐶, 𝐷}) → (𝐴 = 𝐶𝐵 = 𝐷))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 196  wa 382  wo 834  w3a 1071   = wceq 1631  wcel 2145  wne 2943  {cpr 4318
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1870  ax-4 1885  ax-5 1991  ax-6 2057  ax-7 2093  ax-9 2154  ax-10 2174  ax-11 2190  ax-12 2203  ax-13 2408  ax-ext 2751  ax-sep 4915  ax-nul 4923  ax-pr 5034  ax-reg 8653
This theorem depends on definitions:  df-bi 197  df-an 383  df-or 835  df-3an 1073  df-tru 1634  df-ex 1853  df-nf 1858  df-sb 2050  df-eu 2622  df-mo 2623  df-clab 2758  df-cleq 2764  df-clel 2767  df-nfc 2902  df-ne 2944  df-ral 3066  df-rex 3067  df-rab 3070  df-v 3353  df-sbc 3588  df-dif 3726  df-un 3728  df-in 3730  df-ss 3737  df-nul 4064  df-if 4226  df-sn 4317  df-pr 4319  df-op 4323  df-br 4787  df-opab 4847  df-eprel 5162  df-fr 5208
This theorem is referenced by:  preleq  8675
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