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Theorem axregnd 4948
Description: A version of the Axiom of Regularity with no distinct variable conditions.
Assertion
Ref Expression
axregnd (xy → ∃x(xy ⋀ ∀z(zx → ¬ zy)))

Proof of Theorem axregnd
StepHypRef Expression
1 hbnae 1145 . . . . . 6 (¬ ∀z z = x → ∀x ¬ ∀z z = x)
2 hbnae 1145 . . . . . 6 (¬ ∀z z = y → ∀x ¬ ∀z z = y)
31, 2hban 1007 . . . . 5 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → ∀x(¬ ∀z z = x ⋀ ¬ ∀z z = y))
4 hbnae 1145 . . . . . . . 8 (¬ ∀z z = x → ∀z ¬ ∀z z = x)
5 hbnae 1145 . . . . . . . 8 (¬ ∀z z = y → ∀z ¬ ∀z z = y)
64, 5hban 1007 . . . . . . 7 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → ∀z(¬ ∀z z = x ⋀ ¬ ∀z z = y))
7 dveel2 1355 . . . . . . . . 9 (¬ ∀z z = x → (wx → ∀z wx))
87adantr 389 . . . . . . . 8 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → (wx → ∀z wx))
9 dveel2 1355 . . . . . . . . . 10 (¬ ∀z z = y → (wy → ∀z wy))
109adantl 388 . . . . . . . . 9 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → (wy → ∀z wy))
116, 10hbnd 1107 . . . . . . . 8 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → (¬ wy → ∀z ¬ wy))
126, 8, 11hbimd 1108 . . . . . . 7 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → ((wx → ¬ wy) → ∀z(wx → ¬ wy)))
13 elequ1 1134 . . . . . . . . 9 (w = z → (wxzx))
14 elequ1 1134 . . . . . . . . . 10 (w = z → (wyzy))
1514negbid 610 . . . . . . . . 9 (w = z → (¬ wy ↔ ¬ zy))
1613, 15imbi12d 625 . . . . . . . 8 (w = z → ((wx → ¬ wy) ↔ (zx → ¬ zy)))
1716a1i 8 . . . . . . 7 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → (w = z → ((wx → ¬ wy) ↔ (zx → ¬ zy))))
186, 12, 17cbvald 1318 . . . . . 6 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → (∀w(wx → ¬ wy) ↔ ∀z(zx → ¬ zy)))
1918anbi2d 615 . . . . 5 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → ((xy ⋀ ∀w(wx → ¬ wy)) ↔ (xy ⋀ ∀z(zx → ¬ zy))))
203, 19exbid 1103 . . . 4 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → (∃x(xy ⋀ ∀w(wx → ¬ wy)) ↔ ∃x(xy ⋀ ∀z(zx → ¬ zy))))
21 axregndlem2 4947 . . . 4 (xy → ∃x(xy ⋀ ∀w(wx → ¬ wy)))
2220, 21syl5bi 208 . . 3 ((¬ ∀z z = x ⋀ ¬ ∀z z = y) → (xy → ∃x(xy ⋀ ∀z(zx → ¬ zy))))
2322ex 373 . 2 (¬ ∀z z = x → (¬ ∀z z = y → (xy → ∃x(xy ⋀ ∀z(zx → ¬ zy)))))
24 axregndlem1 4946 . . 3 (∀x x = z → (xy → ∃x(xy ⋀ ∀z(zx → ¬ zy))))
2524alequcoms 1141 . 2 (∀z z = x → (xy → ∃x(xy ⋀ ∀z(zx → ¬ zy))))
26 hbae 1143 . . . 4 (∀z z = y → ∀xz z = y)
27 elirrv 4590 . . . . . . . . . 10 ¬ zz
28 elequ2 1135 . . . . . . . . . 10 (z = y → (zzzy))
2927, 28mtbii 715 . . . . . . . . 9 (z = y → ¬ zy)
3029a4s 982 . . . . . . . 8 (∀z z = y → ¬ zy)
3130a1d 12 . . . . . . 7 (∀z z = y → (zx → ¬ zy))
3231a5i 987 . . . . . 6 (∀z z = y → ∀z(zx → ¬ zy))
3332anim2i 335 . . . . 5 ((xy ⋀ ∀z z = y) → (xy ⋀ ∀z(zx → ¬ zy)))
3433expcom 374 . . . 4 (∀z z = y → (xy → (xy ⋀ ∀z(zx → ¬ zy))))
3526, 3419.22d 1060 . . 3 (∀z z = y → (∃x xy → ∃x(xy ⋀ ∀z(zx → ¬ zy))))
36 19.8a 1027 . . 3 (xy → ∃x xy)
3735, 36syl5 21 . 2 (∀z z = y → (xy → ∃x(xy ⋀ ∀z(zx → ¬ zy))))
3823, 25, 37pm2.61ii 130 1 (xy → ∃x(xy ⋀ ∀z(zx → ¬ zy)))
Colors of variables: wff set class
Syntax hints:  ¬ wn 2   → wi 3   ↔ wb 146   ⋀ wa 223  ∀wal 952   = wceq 954   ∈ wcel 956  ∃wex 978
This theorem is referenced by:  zfcndreg 4961
This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 960  ax-gen 961  ax-8 962  ax-10 964  ax-11 965  ax-12 966  ax-13 967  ax-14 968  ax-17 969  ax-4 971  ax-5o 973  ax-6o 976  ax-9o 1121  ax-10o 1138  ax-16 1208  ax-11o 1216  ax-15 1358  ax-ext 1457  ax-sep 2699  ax-pow 2738  ax-reg 4585
This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225  df-ex 979  df-sb 1170  df-eu 1380  df-mo 1381  df-clab 1462  df-cleq 1467  df-clel 1470  df-ne 1584  df-ral 1646  df-rex 1647  df-v 1808  df-dif 2045  df-un 2046  df-in 2047  df-ss 2049  df-nul 2277  df-pw 2398  df-sn 2408  df-pr 2409
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