Theorem pweqb 4195

Description: Classes are equal if and only if their power classes are equal. Exercise 19 of [TakeutiZaring] p. 18. (Contributed by NM, 13-Oct-1996.)

Assertion

Ref	Expression
pweqb	|- ( A = B <-> ~P A = ~P B )

Proof of Theorem pweqb

Step	Hyp	Ref	Expression
1		sspwb 4188	. . 3 |- ( A C_ B <-> ~P A C_ ~P B )
2		sspwb 4188	. . 3 |- ( B C_ A <-> ~P B C_ ~P A )
3	1, 2	anbi12i 456	. 2 |- ( ( A C_ B /\ B C_ A ) <-> ( ~P A C_ ~P B /\ ~P B C_ ~P A ) )
4		eqss 3152	. 2 |- ( A = B <-> ( A C_ B /\ B C_ A ) )
5		eqss 3152	. 2 |- ( ~P A = ~P B <-> ( ~P A C_ ~P B /\ ~P B C_ ~P A ) )
6	3, 4, 5	3bitr4i 211	1 |- ( A = B <-> ~P A = ~P B )

Syntax hints:   /\ wa 103   <-> wb 104   = wceq 1342   C_ wss 3111   ~Pcpw 3553

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 699  ax-5 1434  ax-7 1435  ax-gen 1436  ax-ie1 1480  ax-ie2 1481  ax-8 1491  ax-10 1492  ax-11 1493  ax-i12 1494  ax-bndl 1496  ax-4 1497  ax-17 1513  ax-i9 1517  ax-ial 1521  ax-i5r 1522  ax-14 2138  ax-ext 2146  ax-sep 4094  ax-pow 4147

This theorem depends on definitions:  df-bi 116  df-tru 1345  df-nf 1448  df-sb 1750  df-clab 2151  df-cleq 2157  df-clel 2160  df-nfc 2295  df-v 2723  df-in 3117  df-ss 3124  df-pw 3555  df-sn 3576

This theorem is referenced by: (None)