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Theorem ordpwsucss 4567
Description: The collection of ordinals in the power class of an ordinal is a superset of its successor.

We can think of  ( ~P A  i^i  On ) as another possible definition of successor, which would be equivalent to df-suc 4372 given excluded middle. It is an ordinal, and has some successor-like properties. For example, if  A  e.  On then both  U. suc  A  =  A (onunisuci 4433) and  U. { x  e.  On  |  x  C_  A }  =  A (onuniss2 4512).

Constructively  ( ~P A  i^i  On ) and  suc  A cannot be shown to be equivalent (as proved at ordpwsucexmid 4570). (Contributed by Jim Kingdon, 21-Jul-2019.)

Assertion
Ref Expression
ordpwsucss  |-  ( Ord 
A  ->  suc  A  C_  ( ~P A  i^i  On ) )

Proof of Theorem ordpwsucss
Dummy variable  x is distinct from all other variables.
StepHypRef Expression
1 ordsuc 4563 . . . . 5  |-  ( Ord 
A  <->  Ord  suc  A )
2 ordelon 4384 . . . . . 6  |-  ( ( Ord  suc  A  /\  x  e.  suc  A )  ->  x  e.  On )
32ex 115 . . . . 5  |-  ( Ord 
suc  A  ->  ( x  e.  suc  A  ->  x  e.  On )
)
41, 3sylbi 121 . . . 4  |-  ( Ord 
A  ->  ( x  e.  suc  A  ->  x  e.  On ) )
5 ordtr 4379 . . . . 5  |-  ( Ord 
A  ->  Tr  A
)
6 trsucss 4424 . . . . 5  |-  ( Tr  A  ->  ( x  e.  suc  A  ->  x  C_  A ) )
75, 6syl 14 . . . 4  |-  ( Ord 
A  ->  ( x  e.  suc  A  ->  x  C_  A ) )
84, 7jcad 307 . . 3  |-  ( Ord 
A  ->  ( x  e.  suc  A  ->  (
x  e.  On  /\  x  C_  A ) ) )
9 elin 3319 . . . 4  |-  ( x  e.  ( ~P A  i^i  On )  <->  ( x  e.  ~P A  /\  x  e.  On ) )
10 velpw 3583 . . . . 5  |-  ( x  e.  ~P A  <->  x  C_  A
)
1110anbi2ci 459 . . . 4  |-  ( ( x  e.  ~P A  /\  x  e.  On ) 
<->  ( x  e.  On  /\  x  C_  A )
)
129, 11bitri 184 . . 3  |-  ( x  e.  ( ~P A  i^i  On )  <->  ( x  e.  On  /\  x  C_  A ) )
138, 12imbitrrdi 162 . 2  |-  ( Ord 
A  ->  ( x  e.  suc  A  ->  x  e.  ( ~P A  i^i  On ) ) )
1413ssrdv 3162 1  |-  ( Ord 
A  ->  suc  A  C_  ( ~P A  i^i  On ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 104    e. wcel 2148    i^i cin 3129    C_ wss 3130   ~Pcpw 3576   Tr wtr 4102   Ord word 4363   Oncon0 4364   suc csuc 4366
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 614  ax-in2 615  ax-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-ext 2159  ax-setind 4537
This theorem depends on definitions:  df-bi 117  df-3an 980  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ral 2460  df-rex 2461  df-v 2740  df-dif 3132  df-un 3134  df-in 3136  df-ss 3143  df-pw 3578  df-sn 3599  df-pr 3600  df-uni 3811  df-tr 4103  df-iord 4367  df-on 4369  df-suc 4372
This theorem is referenced by: (None)
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