Theorem tpid1 4664

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 2798	. . 3 ⊢ 𝐴 = 𝐴
2	1	3mix1i 1330	. 2 ⊢ (𝐴 = 𝐴 ∨ 𝐴 = 𝐵 ∨ 𝐴 = 𝐶)
3		tpid1.1	. . 3 ⊢ 𝐴 ∈ V
4	3	eltp 4586	. 2 ⊢ (𝐴 ∈ {𝐴, 𝐵, 𝐶} ↔ (𝐴 = 𝐴 ∨ 𝐴 = 𝐵 ∨ 𝐴 = 𝐶))
5	2, 4	mpbir 234	1 ⊢ 𝐴 ∈ {𝐴, 𝐵, 𝐶}

Syntax hints:   ∨ w3o 1083   = wceq 1538   ∈ wcel 2111  Vcvv 3441  {ctp 4529

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-ext 2770

This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3or 1085  df-tru 1541  df-ex 1782  df-sb 2070  df-clab 2777  df-cleq 2791  df-clel 2870  df-v 3443  df-un 3886  df-sn 4526  df-pr 4528  df-tp 4530

This theorem is referenced by:  tpnz  4675  wrdl3s3  14317  cffldtocusgr  27237  umgrwwlks2on  27743  s3rn  30648  cyc3evpm  30842  sgnsf  30854  sgncl  31906  prodfzo03  31984  circlevma  32023  circlemethhgt  32024  hgt750lemg  32035  hgt750lemb  32037  hgt750lema  32038  hgt750leme  32039  tgoldbachgtde  32041  tgoldbachgt  32044  kur14lem7  32572  kur14lem9  32574  brtpid1  33064  rabren3dioph  39756  fourierdlem102  42850  fourierdlem114  42862  etransclem48  42924