Theorem abid2 2355

Description: A simplification of class abstraction. Theorem 5.2 of [Quine] p. 35. (Contributed by NM, 26-Dec-1993.)

Assertion

Ref	Expression
abid2	|- { x | x e. A } = A

Distinct variable group:   x, A

Proof of Theorem abid2

Step	Hyp	Ref	Expression
1		biid 171	. . 3 |- ( x e. A <-> x e. A )
2	1	abbi2i 2347	. 2 |- A = { x | x e. A }
3	2	eqcomi 2236	1 |- { x | x e. A } = A

Syntax hints:   = wceq 1398   e. wcel 2203   {cab 2218

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-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-11 1555  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-ext 2214

This theorem depends on definitions:  df-bi 117  df-nf 1510  df-sb 1812  df-clab 2219  df-cleq 2225  df-clel 2228

This theorem is referenced by:  csbid  3146  abss  3307  ssab  3308  abssi  3313  notab  3491  inrab2  3494  dfrab2  3496  dfrab3  3497  notrab  3498  eusn  3765  dfopg  3881  iunid  4047  csbexga  4238  imai  5118  dffv4g  5667  frec0g  6628  dfixp  6935  euen1b  7043  modom2  7062  acfun  7514  ccfunen  7578  ballotfilem2  13142