Theorem preq2 3661

Description: Equality theorem for unordered pairs. (Contributed by NM, 5-Aug-1993.)

Assertion

Ref	Expression
preq2	|- ( A = B -> { C , A } = { C , B } )

Proof of Theorem preq2

Step	Hyp	Ref	Expression
1		preq1 3660	. 2 |- ( A = B -> { A , C } = { B , C } )
2		prcom 3659	. 2 |- { C , A } = { A , C }
3		prcom 3659	. 2 |- { C , B } = { B , C }
4	1, 2, 3	3eqtr4g 2228	1 |- ( A = B -> { C , A } = { C , B } )

Syntax hints:   -> wi 4   = wceq 1348   {cpr 3584

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 704  ax-5 1440  ax-7 1441  ax-gen 1442  ax-ie1 1486  ax-ie2 1487  ax-8 1497  ax-10 1498  ax-11 1499  ax-i12 1500  ax-bndl 1502  ax-4 1503  ax-17 1519  ax-i9 1523  ax-ial 1527  ax-i5r 1528  ax-ext 2152

This theorem depends on definitions:  df-bi 116  df-tru 1351  df-nf 1454  df-sb 1756  df-clab 2157  df-cleq 2163  df-clel 2166  df-nfc 2301  df-v 2732  df-un 3125  df-sn 3589  df-pr 3590

This theorem is referenced by:  preq12  3662  preq2i  3664  preq2d  3667  tpeq2  3670  preq12bg  3760  opeq2  3766  uniprg  3811  intprg  3864  prexg  4196  opth  4222  opeqsn  4237  relop  4761  funopg  5232  pr2ne  7169  hashprg  10743  bj-prexg  13946