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Theorem nalset 1482
Description: No set contains all sets. Theorem 41 of [Suppes] p. 30.
Assertion
Ref Expression
nalset ¬ ∃xy yx
Distinct variable group(s):   x,y

Proof of Theorem nalset
StepHypRef Expression
1 alexn 726 . 2 (∀xy ¬ yx ↔ ¬ ∃xy yx)
2 visset 1350 . . . 4 xV
32zfaus 1480 . . 3 yz(zy ↔ (zx ∧ ¬ zz))
4 a13b 819 . . . . . . 7 (z = y → (zyyy))
5 a13b 819 . . . . . . . 8 (z = y → (zxyx))
6 a13b 819 . . . . . . . . . 10 (z = y → (zzyz))
7 a14b 820 . . . . . . . . . 10 (z = y → (yzyy))
86, 7bitrd 406 . . . . . . . . 9 (z = y → (zzyy))
98negbid 463 . . . . . . . 8 (z = y → (¬ zz ↔ ¬ yy))
105, 9anbi12d 476 . . . . . . 7 (z = y → ((zx ∧ ¬ zz) ↔ (yx ∧ ¬ yy)))
114, 10bibi12d 477 . . . . . 6 (z = y → ((zy ↔ (zx ∧ ¬ zz)) ↔ (yy ↔ (yx ∧ ¬ yy))))
1211a4b1 928 . . . . 5 (∀z(zy ↔ (zx ∧ ¬ zz)) → (yy ↔ (yx ∧ ¬ yy)))
13 pclem6 555 . . . . 5 ((yy ↔ (yx ∧ ¬ yy)) → ¬ yx)
1412, 13syl 12 . . . 4 (∀z(zy ↔ (zx ∧ ¬ zz)) → ¬ yx)
151419.22i 723 . . 3 (∃yz(zy ↔ (zx ∧ ¬ zz)) → ∃y ¬ yx)
163, 15ax-mp 6 . 2 y ¬ yx
171, 16mpgbi 685 1 ¬ ∃xy yx
Colors of variables: wff set class
Syntax hints:  ¬ wn 1   ↔ wb 127   ∧ wa 196  ∀wal 672  ∃wex 678   = weq 797   ∈ wel 803
This theorem is referenced by:  nvelv 1483  kmlem2 3581
This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6  ax-4 673  ax-5 674  ax-6 675  ax-7 676  ax-gen 677  ax-8 798  ax-9 799  ax-12 802  ax-13 804  ax-14 805  ax-17 925  ax-ext 1074  ax-rep 1075
This theorem depends on definitions:  df-bi 128  df-an 198  df-ex 679  df-sb 853  df-clab 1093  df-cleq 1097  df-clel 1099  df-v 1349
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