Theorem tpid1 4735

Description: One of the three elements of an unordered triple. (Contributed by NM, 7-Apr-1994.) (Proof shortened by Andrew Salmon, 29-Jun-2011.)

Hypothesis

Ref	Expression
tpid1.1	⊢ 𝐴 ∈ V

Assertion

Ref	Expression
tpid1	⊢ 𝐴 ∈ {𝐴, 𝐵, 𝐶}

Proof of Theorem tpid1

Step	Hyp	Ref	Expression
1		eqid 2730	. . 3 ⊢ 𝐴 = 𝐴
2	1	3mix1i 1334	. 2 ⊢ (𝐴 = 𝐴 ∨ 𝐴 = 𝐵 ∨ 𝐴 = 𝐶)
3		tpid1.1	. . 3 ⊢ 𝐴 ∈ V
4	3	eltp 4656	. 2 ⊢ (𝐴 ∈ {𝐴, 𝐵, 𝐶} ↔ (𝐴 = 𝐴 ∨ 𝐴 = 𝐵 ∨ 𝐴 = 𝐶))
5	2, 4	mpbir 231	1 ⊢ 𝐴 ∈ {𝐴, 𝐵, 𝐶}

Syntax hints:   ∨ w3o 1085   = wceq 1540   ∈ wcel 2109  Vcvv 3450  {ctp 4596

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-ext 2702

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3or 1087  df-tru 1543  df-ex 1780  df-sb 2066  df-clab 2709  df-cleq 2722  df-clel 2804  df-v 3452  df-un 3922  df-sn 4593  df-pr 4595  df-tp 4597

This theorem is referenced by:  tpnz  4746  hash3tpb  14467  wrdl3s3  14935  cffldtocusgr  29381  cffldtocusgrOLD  29382  umgrwwlks2on  29894  sgncl  32763  s3rnOLD  32874  cyc3evpm  33114  sgnsf  33126  prodfzo03  34601  circlevma  34640  circlemethhgt  34641  hgt750lemg  34652  hgt750lemb  34654  hgt750lema  34655  hgt750leme  34656  tgoldbachgtde  34658  tgoldbachgt  34661  kur14lem7  35206  kur14lem9  35208  brtpid1  35715  rabren3dioph  42810  fourierdlem102  46213  fourierdlem114  46225  etransclem48  46287  usgrexmpl1tri  48020  usgrexmpl2nb0  48026  usgrexmpl2nb1  48027  usgrexmpl2nb2  48028  usgrexmpl2nb3  48029  usgrexmpl2nb4  48030  usgrexmpl2nb5  48031  gpg3kgrtriex  48084