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Theorem axunnd 9706
Description: A version of the Axiom of Union with no distinct variable conditions. (Contributed by NM, 2-Jan-2002.)
Assertion
Ref Expression
axunnd 𝑥𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥)

Proof of Theorem axunnd
Dummy variable 𝑤 is distinct from all other variables.
StepHypRef Expression
1 axunndlem1 9705 . . . 4 𝑤𝑦(∃𝑤(𝑦𝑤𝑤𝑧) → 𝑦𝑤)
2 nfnae 2441 . . . . . 6 𝑥 ¬ ∀𝑥 𝑥 = 𝑦
3 nfnae 2441 . . . . . 6 𝑥 ¬ ∀𝑥 𝑥 = 𝑧
42, 3nfan 1999 . . . . 5 𝑥(¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧)
5 nfnae 2441 . . . . . . 7 𝑦 ¬ ∀𝑥 𝑥 = 𝑦
6 nfnae 2441 . . . . . . 7 𝑦 ¬ ∀𝑥 𝑥 = 𝑧
75, 6nfan 1999 . . . . . 6 𝑦(¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧)
8 nfv 2010 . . . . . . . 8 𝑤(¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧)
9 nfcvf 2965 . . . . . . . . . . 11 (¬ ∀𝑥 𝑥 = 𝑦𝑥𝑦)
109adantr 473 . . . . . . . . . 10 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → 𝑥𝑦)
11 nfcvd 2942 . . . . . . . . . 10 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → 𝑥𝑤)
1210, 11nfeld 2950 . . . . . . . . 9 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → Ⅎ𝑥 𝑦𝑤)
13 nfcvf 2965 . . . . . . . . . . 11 (¬ ∀𝑥 𝑥 = 𝑧𝑥𝑧)
1413adantl 474 . . . . . . . . . 10 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → 𝑥𝑧)
1511, 14nfeld 2950 . . . . . . . . 9 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → Ⅎ𝑥 𝑤𝑧)
1612, 15nfand 1997 . . . . . . . 8 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → Ⅎ𝑥(𝑦𝑤𝑤𝑧))
178, 16nfexd 2352 . . . . . . 7 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → Ⅎ𝑥𝑤(𝑦𝑤𝑤𝑧))
1817, 12nfimd 1993 . . . . . 6 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → Ⅎ𝑥(∃𝑤(𝑦𝑤𝑤𝑧) → 𝑦𝑤))
197, 18nfald 2351 . . . . 5 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → Ⅎ𝑥𝑦(∃𝑤(𝑦𝑤𝑤𝑧) → 𝑦𝑤))
20 nfcvd 2942 . . . . . . . . 9 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → 𝑦𝑤)
21 nfcvf2 2966 . . . . . . . . . 10 (¬ ∀𝑥 𝑥 = 𝑦𝑦𝑥)
2221adantr 473 . . . . . . . . 9 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → 𝑦𝑥)
2320, 22nfeqd 2949 . . . . . . . 8 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → Ⅎ𝑦 𝑤 = 𝑥)
247, 23nfan1 2232 . . . . . . 7 𝑦((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) ∧ 𝑤 = 𝑥)
25 elequ2 2171 . . . . . . . . . . . 12 (𝑤 = 𝑥 → (𝑦𝑤𝑦𝑥))
26 elequ1 2164 . . . . . . . . . . . 12 (𝑤 = 𝑥 → (𝑤𝑧𝑥𝑧))
2725, 26anbi12d 625 . . . . . . . . . . 11 (𝑤 = 𝑥 → ((𝑦𝑤𝑤𝑧) ↔ (𝑦𝑥𝑥𝑧)))
2827a1i 11 . . . . . . . . . 10 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → (𝑤 = 𝑥 → ((𝑦𝑤𝑤𝑧) ↔ (𝑦𝑥𝑥𝑧))))
294, 16, 28cbvexd 2415 . . . . . . . . 9 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → (∃𝑤(𝑦𝑤𝑤𝑧) ↔ ∃𝑥(𝑦𝑥𝑥𝑧)))
3029adantr 473 . . . . . . . 8 (((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) ∧ 𝑤 = 𝑥) → (∃𝑤(𝑦𝑤𝑤𝑧) ↔ ∃𝑥(𝑦𝑥𝑥𝑧)))
3125adantl 474 . . . . . . . 8 (((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) ∧ 𝑤 = 𝑥) → (𝑦𝑤𝑦𝑥))
3230, 31imbi12d 336 . . . . . . 7 (((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) ∧ 𝑤 = 𝑥) → ((∃𝑤(𝑦𝑤𝑤𝑧) → 𝑦𝑤) ↔ (∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥)))
3324, 32albid 2257 . . . . . 6 (((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) ∧ 𝑤 = 𝑥) → (∀𝑦(∃𝑤(𝑦𝑤𝑤𝑧) → 𝑦𝑤) ↔ ∀𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥)))
3433ex 402 . . . . 5 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → (𝑤 = 𝑥 → (∀𝑦(∃𝑤(𝑦𝑤𝑤𝑧) → 𝑦𝑤) ↔ ∀𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥))))
354, 19, 34cbvexd 2415 . . . 4 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → (∃𝑤𝑦(∃𝑤(𝑦𝑤𝑤𝑧) → 𝑦𝑤) ↔ ∃𝑥𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥)))
361, 35mpbii 225 . . 3 ((¬ ∀𝑥 𝑥 = 𝑦 ∧ ¬ ∀𝑥 𝑥 = 𝑧) → ∃𝑥𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥))
3736ex 402 . 2 (¬ ∀𝑥 𝑥 = 𝑦 → (¬ ∀𝑥 𝑥 = 𝑧 → ∃𝑥𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥)))
38 nfae 2439 . . . 4 𝑦𝑥 𝑥 = 𝑦
39 nfae 2439 . . . . . 6 𝑥𝑥 𝑥 = 𝑦
40 elirrv 8743 . . . . . . . . 9 ¬ 𝑦𝑦
41 elequ2 2171 . . . . . . . . 9 (𝑥 = 𝑦 → (𝑦𝑥𝑦𝑦))
4240, 41mtbiri 319 . . . . . . . 8 (𝑥 = 𝑦 → ¬ 𝑦𝑥)
4342intnanrd 484 . . . . . . 7 (𝑥 = 𝑦 → ¬ (𝑦𝑥𝑥𝑧))
4443sps 2219 . . . . . 6 (∀𝑥 𝑥 = 𝑦 → ¬ (𝑦𝑥𝑥𝑧))
4539, 44nexd 2256 . . . . 5 (∀𝑥 𝑥 = 𝑦 → ¬ ∃𝑥(𝑦𝑥𝑥𝑧))
4645pm2.21d 119 . . . 4 (∀𝑥 𝑥 = 𝑦 → (∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥))
4738, 46alrimi 2248 . . 3 (∀𝑥 𝑥 = 𝑦 → ∀𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥))
48 19.8a 2216 . . 3 (∀𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥) → ∃𝑥𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥))
4947, 48syl 17 . 2 (∀𝑥 𝑥 = 𝑦 → ∃𝑥𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥))
50 nfae 2439 . . . 4 𝑦𝑥 𝑥 = 𝑧
51 nfae 2439 . . . . . 6 𝑥𝑥 𝑥 = 𝑧
52 elirrv 8743 . . . . . . . . 9 ¬ 𝑧𝑧
53 elequ1 2164 . . . . . . . . 9 (𝑥 = 𝑧 → (𝑥𝑧𝑧𝑧))
5452, 53mtbiri 319 . . . . . . . 8 (𝑥 = 𝑧 → ¬ 𝑥𝑧)
5554intnand 483 . . . . . . 7 (𝑥 = 𝑧 → ¬ (𝑦𝑥𝑥𝑧))
5655sps 2219 . . . . . 6 (∀𝑥 𝑥 = 𝑧 → ¬ (𝑦𝑥𝑥𝑧))
5751, 56nexd 2256 . . . . 5 (∀𝑥 𝑥 = 𝑧 → ¬ ∃𝑥(𝑦𝑥𝑥𝑧))
5857pm2.21d 119 . . . 4 (∀𝑥 𝑥 = 𝑧 → (∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥))
5950, 58alrimi 2248 . . 3 (∀𝑥 𝑥 = 𝑧 → ∀𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥))
6059, 48syl 17 . 2 (∀𝑥 𝑥 = 𝑧 → ∃𝑥𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥))
6137, 49, 60pm2.61ii 178 1 𝑥𝑦(∃𝑥(𝑦𝑥𝑥𝑧) → 𝑦𝑥)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 198  wa 385  wal 1651  wex 1875  wnfc 2928
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1891  ax-4 1905  ax-5 2006  ax-6 2072  ax-7 2107  ax-8 2159  ax-9 2166  ax-10 2185  ax-11 2200  ax-12 2213  ax-13 2377  ax-ext 2777  ax-sep 4975  ax-nul 4983  ax-pr 5097  ax-un 7183  ax-reg 8739
This theorem depends on definitions:  df-bi 199  df-an 386  df-or 875  df-3an 1110  df-tru 1657  df-ex 1876  df-nf 1880  df-sb 2065  df-mo 2591  df-eu 2609  df-clab 2786  df-cleq 2792  df-clel 2795  df-nfc 2930  df-ne 2972  df-ral 3094  df-rex 3095  df-rab 3098  df-v 3387  df-sbc 3634  df-dif 3772  df-un 3774  df-in 3776  df-ss 3783  df-nul 4116  df-if 4278  df-sn 4369  df-pr 4371  df-op 4375  df-br 4844  df-opab 4906  df-eprel 5225  df-fr 5271
This theorem is referenced by:  zfcndun  9725  axunprim  32095
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