Theorem dftr4 4757

Description: An alternate way of defining a transitive class. Definition of [Enderton] p. 71. (Contributed by NM, 29-Aug-1993.)

Assertion

Ref	Expression
dftr4	|- ( Tr A <-> A C_ ~P A )

Proof of Theorem dftr4

Step	Hyp	Ref	Expression
1		df-tr 4753	. 2 |- ( Tr A <-> U. A C_ A )
2		sspwuni 4611	. 2 |- ( A C_ ~P A <-> U. A C_ A )
3	1, 2	bitr4i 267	1 |- ( Tr A <-> A C_ ~P A )

Syntax hints:   <-> wb 196   C_ wss 3574   ~Pcpw 4158   U.cuni 4436   Tr wtr 4752

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ral 2917  df-v 3202  df-in 3581  df-ss 3588  df-pw 4160  df-uni 4437  df-tr 4753

This theorem is referenced by:  tr0  4764  pwtr  4921  r1ordg  8641  r1sssuc  8646  r1val1  8649  ackbij2lem3  9063  tsktrss  9583