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Theorem suctr 4491
Description: The successor of a transtive class is transitive. (Contributed by Alan Sare, 11-Apr-2009.)
Assertion
Ref Expression
suctr  |-  ( Tr  A  ->  Tr  suc  A
)

Proof of Theorem suctr
Dummy variables  y 
z are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 simpr 447 . . . . 5  |-  ( ( z  e.  y  /\  y  e.  suc  A )  ->  y  e.  suc  A )
2 vex 2804 . . . . . 6  |-  y  e. 
_V
32elsuc 4477 . . . . 5  |-  ( y  e.  suc  A  <->  ( y  e.  A  \/  y  =  A ) )
41, 3sylib 188 . . . 4  |-  ( ( z  e.  y  /\  y  e.  suc  A )  ->  ( y  e.  A  \/  y  =  A ) )
5 simpl 443 . . . . . . 7  |-  ( ( z  e.  y  /\  y  e.  suc  A )  ->  z  e.  y )
6 eleq2 2357 . . . . . . 7  |-  ( y  =  A  ->  (
z  e.  y  <->  z  e.  A ) )
75, 6syl5ibcom 211 . . . . . 6  |-  ( ( z  e.  y  /\  y  e.  suc  A )  ->  ( y  =  A  ->  z  e.  A ) )
8 elelsuc 4480 . . . . . 6  |-  ( z  e.  A  ->  z  e.  suc  A )
97, 8syl6 29 . . . . 5  |-  ( ( z  e.  y  /\  y  e.  suc  A )  ->  ( y  =  A  ->  z  e.  suc  A ) )
10 trel 4136 . . . . . . . . 9  |-  ( Tr  A  ->  ( (
z  e.  y  /\  y  e.  A )  ->  z  e.  A ) )
1110exp3a 425 . . . . . . . 8  |-  ( Tr  A  ->  ( z  e.  y  ->  ( y  e.  A  ->  z  e.  A ) ) )
1211adantrd 454 . . . . . . 7  |-  ( Tr  A  ->  ( (
z  e.  y  /\  y  e.  suc  A )  ->  ( y  e.  A  ->  z  e.  A ) ) )
1312, 8syl8 65 . . . . . 6  |-  ( Tr  A  ->  ( (
z  e.  y  /\  y  e.  suc  A )  ->  ( y  e.  A  ->  z  e.  suc  A ) ) )
14 jao 498 . . . . . 6  |-  ( ( y  e.  A  -> 
z  e.  suc  A
)  ->  ( (
y  =  A  -> 
z  e.  suc  A
)  ->  ( (
y  e.  A  \/  y  =  A )  ->  z  e.  suc  A
) ) )
1513, 14syl6 29 . . . . 5  |-  ( Tr  A  ->  ( (
z  e.  y  /\  y  e.  suc  A )  ->  ( ( y  =  A  ->  z  e.  suc  A )  -> 
( ( y  e.  A  \/  y  =  A )  ->  z  e.  suc  A ) ) ) )
169, 15mpdi 38 . . . 4  |-  ( Tr  A  ->  ( (
z  e.  y  /\  y  e.  suc  A )  ->  ( ( y  e.  A  \/  y  =  A )  ->  z  e.  suc  A ) ) )
174, 16mpdi 38 . . 3  |-  ( Tr  A  ->  ( (
z  e.  y  /\  y  e.  suc  A )  ->  z  e.  suc  A ) )
1817alrimivv 1622 . 2  |-  ( Tr  A  ->  A. z A. y ( ( z  e.  y  /\  y  e.  suc  A )  -> 
z  e.  suc  A
) )
19 dftr2 4131 . 2  |-  ( Tr 
suc  A  <->  A. z A. y
( ( z  e.  y  /\  y  e. 
suc  A )  -> 
z  e.  suc  A
) )
2018, 19sylibr 203 1  |-  ( Tr  A  ->  Tr  suc  A
)
Colors of variables: wff set class
Syntax hints:    -> wi 4    \/ wo 357    /\ wa 358   A.wal 1530    = wceq 1632    e. wcel 1696   Tr wtr 4129   suc csuc 4410
This theorem is referenced by:  dfon2lem3  24212  dfon2lem7  24216  dford3lem2  27223
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1536  ax-5 1547  ax-17 1606  ax-9 1644  ax-8 1661  ax-6 1715  ax-7 1720  ax-11 1727  ax-12 1878  ax-ext 2277
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-tru 1310  df-ex 1532  df-nf 1535  df-sb 1639  df-clab 2283  df-cleq 2289  df-clel 2292  df-nfc 2421  df-v 2803  df-un 3170  df-in 3172  df-ss 3179  df-sn 3659  df-uni 3844  df-tr 4130  df-suc 4414
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