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Theorem trel 4553
Description: In a transitive class, the membership relation is transitive. (Contributed by NM, 19-Apr-1994.) (Proof shortened by Andrew Salmon, 9-Jul-2011.)
Assertion
Ref Expression
trel  |-  ( Tr  A  ->  ( ( B  e.  C  /\  C  e.  A )  ->  B  e.  A ) )

Proof of Theorem trel
Dummy variables  x  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 dftr2 4548 . 2  |-  ( Tr  A  <->  A. y A. x
( ( y  e.  x  /\  x  e.  A )  ->  y  e.  A ) )
2 eleq12 2543 . . . . . 6  |-  ( ( y  =  B  /\  x  =  C )  ->  ( y  e.  x  <->  B  e.  C ) )
3 eleq1 2539 . . . . . . 7  |-  ( x  =  C  ->  (
x  e.  A  <->  C  e.  A ) )
43adantl 466 . . . . . 6  |-  ( ( y  =  B  /\  x  =  C )  ->  ( x  e.  A  <->  C  e.  A ) )
52, 4anbi12d 710 . . . . 5  |-  ( ( y  =  B  /\  x  =  C )  ->  ( ( y  e.  x  /\  x  e.  A )  <->  ( B  e.  C  /\  C  e.  A ) ) )
6 eleq1 2539 . . . . . 6  |-  ( y  =  B  ->  (
y  e.  A  <->  B  e.  A ) )
76adantr 465 . . . . 5  |-  ( ( y  =  B  /\  x  =  C )  ->  ( y  e.  A  <->  B  e.  A ) )
85, 7imbi12d 320 . . . 4  |-  ( ( y  =  B  /\  x  =  C )  ->  ( ( ( y  e.  x  /\  x  e.  A )  ->  y  e.  A )  <->  ( ( B  e.  C  /\  C  e.  A )  ->  B  e.  A ) ) )
98spc2gv 3206 . . 3  |-  ( ( B  e.  C  /\  C  e.  A )  ->  ( A. y A. x ( ( y  e.  x  /\  x  e.  A )  ->  y  e.  A )  ->  (
( B  e.  C  /\  C  e.  A
)  ->  B  e.  A ) ) )
109pm2.43b 50 . 2  |-  ( A. y A. x ( ( y  e.  x  /\  x  e.  A )  ->  y  e.  A )  ->  ( ( B  e.  C  /\  C  e.  A )  ->  B  e.  A ) )
111, 10sylbi 195 1  |-  ( Tr  A  ->  ( ( B  e.  C  /\  C  e.  A )  ->  B  e.  A ) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    <-> wb 184    /\ wa 369   A.wal 1377    = wceq 1379    e. wcel 1767   Tr wtr 4546
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1601  ax-4 1612  ax-5 1680  ax-6 1719  ax-7 1739  ax-10 1786  ax-11 1791  ax-12 1803  ax-13 1968  ax-ext 2445
This theorem depends on definitions:  df-bi 185  df-an 371  df-tru 1382  df-ex 1597  df-nf 1600  df-sb 1712  df-clab 2453  df-cleq 2459  df-clel 2462  df-nfc 2617  df-v 3120  df-in 3488  df-ss 3495  df-uni 4252  df-tr 4547
This theorem is referenced by:  trel3  4554  trintss  4562  ordn2lp  4904  ordelord  4906  tz7.7  4910  ordtr1  4927  suctr  4967  trsuc  4968  ordom  6704  elnn  6705  epfrs  8174  tcrank  8314  dfon2lem6  29147  tratrb  32787  truniALT  32793  onfrALTlem2  32799  trelded  32819  pwtrrVD  33106  suctrALT  33107  suctrALT2VD  33117  suctrALT2  33118  tratrbVD  33142  truniALTVD  33159  trintALTVD  33161  trintALT  33162  onfrALTlem2VD  33170  suctrALTcf  33203  suctrALTcfVD  33204
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