Theorem elpw 3365

Description: Membership in a power class. Theorem 86 of [Suppes] p. 47. (Contributed by NM, 31-Dec-1993.)

Hypothesis

Ref	Expression
elpw.1	|- A e. _V

Assertion

Ref	Expression
elpw	|- ( A e. ~P B <-> A C_ B )

Proof of Theorem elpw

Dummy variable x is distinct from all other variables.

Step	Hyp	Ref	Expression
1		elpw.1	. 2 |- A e. _V
2		sseq1 2966	. 2 |- ( x = A -> ( x C_ B <-> A C_ B ) )
3		df-pw 3361	. 2 |- ~P B = { x | x C_ B }
4	1, 2, 3	elab2 2690	1 |- ( A e. ~P B <-> A C_ B )

Syntax hints:   <-> wb 98   e. wcel 1393   _Vcvv 2557   C_ wss 2917   ~Pcpw 3359

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022

This theorem depends on definitions:  df-bi 110  df-tru 1246  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-v 2559  df-in 2924  df-ss 2931  df-pw 3361

This theorem is referenced by:  selpw  3366  elpwg  3367  prsspw  3536  pwprss  3576  pwtpss  3577  pwv  3579  sspwuni  3739  iinpw  3742  iunpwss  3743  0elpw  3917  pwuni  3943  snelpw  3949  sspwb  3952  ssextss  3956  pwin  4019  pwunss  4020  iunpw  4211  xpsspw  4450  ioof  8840