Theorem tpid1 4704

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 2821	. . 3 ⊢ 𝐴 = 𝐴
2	1	3mix1i 1329	. 2 ⊢ (𝐴 = 𝐴 ∨ 𝐴 = 𝐵 ∨ 𝐴 = 𝐶)
3		tpid1.1	. . 3 ⊢ 𝐴 ∈ V
4	3	eltp 4626	. 2 ⊢ (𝐴 ∈ {𝐴, 𝐵, 𝐶} ↔ (𝐴 = 𝐴 ∨ 𝐴 = 𝐵 ∨ 𝐴 = 𝐶))
5	2, 4	mpbir 233	1 ⊢ 𝐴 ∈ {𝐴, 𝐵, 𝐶}

Syntax hints:   ∨ w3o 1082   = wceq 1537   ∈ wcel 2114  Vcvv 3494  {ctp 4571

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2116  ax-9 2124  ax-10 2145  ax-11 2161  ax-12 2177  ax-ext 2793

This theorem depends on definitions:  df-bi 209  df-an 399  df-or 844  df-3or 1084  df-tru 1540  df-ex 1781  df-nf 1785  df-sb 2070  df-clab 2800  df-cleq 2814  df-clel 2893  df-nfc 2963  df-v 3496  df-un 3941  df-sn 4568  df-pr 4570  df-tp 4572

This theorem is referenced by:  tpnz  4714  wrdl3s3  14326  cffldtocusgr  27229  umgrwwlks2on  27736  s3rn  30622  cyc3evpm  30792  sgnsf  30804  sgncl  31796  prodfzo03  31874  circlevma  31913  circlemethhgt  31914  hgt750lemg  31925  hgt750lemb  31927  hgt750lema  31928  hgt750leme  31929  tgoldbachgtde  31931  tgoldbachgt  31934  kur14lem7  32459  kur14lem9  32461  brtpid1  32951  rabren3dioph  39432  fourierdlem102  42513  fourierdlem114  42525  etransclem48  42587