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Theorem eltp 4221
Description: A member of an unordered triple of classes is one of them. Special case of Exercise 1 of [TakeutiZaring] p. 17. (Contributed by NM, 8-Apr-1994.) (Revised by Mario Carneiro, 11-Feb-2015.)
Hypothesis
Ref Expression
eltp.1 𝐴 ∈ V
Assertion
Ref Expression
eltp (𝐴 ∈ {𝐵, 𝐶, 𝐷} ↔ (𝐴 = 𝐵𝐴 = 𝐶𝐴 = 𝐷))

Proof of Theorem eltp
StepHypRef Expression
1 eltp.1 . 2 𝐴 ∈ V
2 eltpg 4218 . 2 (𝐴 ∈ V → (𝐴 ∈ {𝐵, 𝐶, 𝐷} ↔ (𝐴 = 𝐵𝐴 = 𝐶𝐴 = 𝐷)))
31, 2ax-mp 5 1 (𝐴 ∈ {𝐵, 𝐶, 𝐷} ↔ (𝐴 = 𝐵𝐴 = 𝐶𝐴 = 𝐷))
Colors of variables: wff setvar class
Syntax hints:  wb 196  w3o 1035   = wceq 1481  wcel 1988  Vcvv 3195  {ctp 4172
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1720  ax-4 1735  ax-5 1837  ax-6 1886  ax-7 1933  ax-9 1997  ax-10 2017  ax-11 2032  ax-12 2045  ax-13 2244  ax-ext 2600
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1037  df-tru 1484  df-ex 1703  df-nf 1708  df-sb 1879  df-clab 2607  df-cleq 2613  df-clel 2616  df-nfc 2751  df-v 3197  df-un 3572  df-sn 4169  df-pr 4171  df-tp 4173
This theorem is referenced by:  dftp2  4222  tpid1  4294  tpid2  4295  tpres  6451  fntpb  6458  bpoly3  14770  cnfldfunALT  19740  gausslemma2dlem0i  25070  2lgsoddprm  25122  nb3grprlem1  26263  frgr3vlem1  27117  frgr3vlem2  27118  prodtp  29547  hgt750lemb  30708  brtp  31614  sltsolem1  31800  fmtno4prmfac  41249
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