Theorem prcom 3799

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

Assertion

Ref	Expression
prcom	|- {A, B} = {B, A}

Proof of Theorem prcom

Step	Hyp	Ref	Expression
1		uncom 3409	. 2 |- ({A} u. {B}) = ({B} u. {A})
2		df-pr 3743	. 2 |- {A, B} = ({A} u. {B})
3		df-pr 3743	. 2 |- {B, A} = ({B} u. {A})
4	1, 2, 3	3eqtr4i 2383	1 |- {A, B} = {B, A}

Syntax hints:   = wceq 1642   u. cun 3208  {csn 3738  {cpr 3739

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2479  df-v 2862  df-nin 3212  df-compl 3213  df-un 3215  df-pr 3743

This theorem is referenced by:  preq2  3801  tpcoma  3817  tpidm23  3824  prid2g  3827  prid2  3829  difprsn2  3849  snprss2  4122  prprc1  4124  preqr2  4126  preq12b  4128  fvpr2  5451