Theorem snsstp3 3820

Description: A singleton is a subset of an unordered triple containing its member. (Contributed by NM, 9-Oct-2013.)

Assertion

Ref	Expression
snsstp3	|- { C } C_ { A , B , C }

Proof of Theorem snsstp3

Step	Hyp	Ref	Expression
1		ssun2 3368	. 2 |- { C } C_ ( { A , B } u. { C } )
2		df-tp 3674	. 2 |- { A , B , C } = ( { A , B } u. { C } )
3	1, 2	sseqtrri 3259	1 |- { C } C_ { A , B , C }

Syntax hints:   u. cun 3195   C_ wss 3197   {csn 3666   {cpr 3667   {ctp 3668

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 714  ax-5 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-10 1551  ax-11 1552  ax-i12 1553  ax-bndl 1555  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-ext 2211

This theorem depends on definitions:  df-bi 117  df-tru 1398  df-nf 1507  df-sb 1809  df-clab 2216  df-cleq 2222  df-clel 2225  df-nfc 2361  df-v 2801  df-un 3201  df-in 3203  df-ss 3210  df-tp 3674

This theorem is referenced by:  sstpr  3835  prdsmulr  13311  mpocnfldmul  14527  cnfldds  14532