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Theorem eliuniincex 45049
Description: Counterexample to show that the additional conditions in eliuniin 45039 and eliuniin2 45060 are actually needed. Notice that the definition of 𝐴 is not even needed (it can be any class). (Contributed by Glauco Siliprandi, 26-Jun-2021.)
Hypotheses
Ref Expression
eliuniincex.1 𝐵 = {∅}
eliuniincex.2 𝐶 = ∅
eliuniincex.3 𝐷 = ∅
eliuniincex.4 𝑍 = V
Assertion
Ref Expression
eliuniincex ¬ (𝑍𝐴 ↔ ∃𝑥𝐵𝑦𝐶 𝑍𝐷)
Distinct variable groups:   𝑥,𝐵   𝑦,𝐶   𝑥,𝑍
Allowed substitution hints:   𝐴(𝑥,𝑦)   𝐵(𝑦)   𝐶(𝑥)   𝐷(𝑥,𝑦)   𝑍(𝑦)

Proof of Theorem eliuniincex
StepHypRef Expression
1 eliuniincex.4 . . 3 𝑍 = V
2 nvel 5322 . . 3 ¬ V ∈ 𝐴
31, 2eqneltri 2858 . 2 ¬ 𝑍𝐴
4 0ex 5313 . . . . 5 ∅ ∈ V
54snid 4667 . . . 4 ∅ ∈ {∅}
6 eliuniincex.1 . . . 4 𝐵 = {∅}
75, 6eleqtrri 2838 . . 3 ∅ ∈ 𝐵
8 ral0 4519 . . 3 𝑦 ∈ ∅ 𝑍𝐷
9 nfcv 2903 . . . . 5 𝑥
10 nfcv 2903 . . . . . 6 𝑥𝑍
11 eliuniincex.3 . . . . . . 7 𝐷 = ∅
1211, 9nfcxfr 2901 . . . . . 6 𝑥𝐷
1310, 12nfel 2918 . . . . 5 𝑥 𝑍𝐷
149, 13nfral 3372 . . . 4 𝑥𝑦 ∈ ∅ 𝑍𝐷
15 eliuniincex.2 . . . . . 6 𝐶 = ∅
1615raleqi 3322 . . . . 5 (∀𝑦𝐶 𝑍𝐷 ↔ ∀𝑦 ∈ ∅ 𝑍𝐷)
1716a1i 11 . . . 4 (𝑥 = ∅ → (∀𝑦𝐶 𝑍𝐷 ↔ ∀𝑦 ∈ ∅ 𝑍𝐷))
1814, 17rspce 3611 . . 3 ((∅ ∈ 𝐵 ∧ ∀𝑦 ∈ ∅ 𝑍𝐷) → ∃𝑥𝐵𝑦𝐶 𝑍𝐷)
197, 8, 18mp2an 692 . 2 𝑥𝐵𝑦𝐶 𝑍𝐷
20 pm3.22 459 . . . 4 ((¬ 𝑍𝐴 ∧ ∃𝑥𝐵𝑦𝐶 𝑍𝐷) → (∃𝑥𝐵𝑦𝐶 𝑍𝐷 ∧ ¬ 𝑍𝐴))
2120olcd 874 . . 3 ((¬ 𝑍𝐴 ∧ ∃𝑥𝐵𝑦𝐶 𝑍𝐷) → ((𝑍𝐴 ∧ ¬ ∃𝑥𝐵𝑦𝐶 𝑍𝐷) ∨ (∃𝑥𝐵𝑦𝐶 𝑍𝐷 ∧ ¬ 𝑍𝐴)))
22 xor 1016 . . 3 (¬ (𝑍𝐴 ↔ ∃𝑥𝐵𝑦𝐶 𝑍𝐷) ↔ ((𝑍𝐴 ∧ ¬ ∃𝑥𝐵𝑦𝐶 𝑍𝐷) ∨ (∃𝑥𝐵𝑦𝐶 𝑍𝐷 ∧ ¬ 𝑍𝐴)))
2321, 22sylibr 234 . 2 ((¬ 𝑍𝐴 ∧ ∃𝑥𝐵𝑦𝐶 𝑍𝐷) → ¬ (𝑍𝐴 ↔ ∃𝑥𝐵𝑦𝐶 𝑍𝐷))
243, 19, 23mp2an 692 1 ¬ (𝑍𝐴 ↔ ∃𝑥𝐵𝑦𝐶 𝑍𝐷)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wb 206  wa 395  wo 847   = wceq 1537  wcel 2106  wral 3059  wrex 3068  Vcvv 3478  c0 4339  {csn 4631
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1908  ax-6 1965  ax-7 2005  ax-8 2108  ax-9 2116  ax-10 2139  ax-11 2155  ax-12 2175  ax-13 2375  ax-ext 2706  ax-sep 5302  ax-nul 5312
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-tru 1540  df-fal 1550  df-ex 1777  df-nf 1781  df-sb 2063  df-clab 2713  df-cleq 2727  df-clel 2814  df-nfc 2890  df-ral 3060  df-rex 3069  df-v 3480  df-dif 3966  df-nul 4340  df-sn 4632
This theorem is referenced by: (None)
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