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Theorem imai 5043
Description: Image under the identity relation. Theorem 3.16(viii) of [Monk1] p. 38. (Contributed by NM, 30-Apr-1998.)
Assertion
Ref Expression
imai  |-  (  _I  " A )  =  A

Proof of Theorem imai
Dummy variables  x  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 dfima3 5031 . 2  |-  (  _I  " A )  =  {
y  |  E. x
( x  e.  A  /\  <. x ,  y
>.  e.  _I  ) }
2 df-br 4040 . . . . . . . 8  |-  ( x  _I  y  <->  <. x ,  y >.  e.  _I  )
3 vex 2804 . . . . . . . . 9  |-  y  e. 
_V
43ideq 4852 . . . . . . . 8  |-  ( x  _I  y  <->  x  =  y )
52, 4bitr3i 242 . . . . . . 7  |-  ( <.
x ,  y >.  e.  _I  <->  x  =  y
)
65anbi2i 675 . . . . . 6  |-  ( ( x  e.  A  /\  <.
x ,  y >.  e.  _I  )  <->  ( x  e.  A  /\  x  =  y ) )
7 ancom 437 . . . . . 6  |-  ( ( x  e.  A  /\  x  =  y )  <->  ( x  =  y  /\  x  e.  A )
)
86, 7bitri 240 . . . . 5  |-  ( ( x  e.  A  /\  <.
x ,  y >.  e.  _I  )  <->  ( x  =  y  /\  x  e.  A ) )
98exbii 1572 . . . 4  |-  ( E. x ( x  e.  A  /\  <. x ,  y >.  e.  _I  ) 
<->  E. x ( x  =  y  /\  x  e.  A ) )
10 eleq1 2356 . . . . 5  |-  ( x  =  y  ->  (
x  e.  A  <->  y  e.  A ) )
113, 10ceqsexv 2836 . . . 4  |-  ( E. x ( x  =  y  /\  x  e.  A )  <->  y  e.  A )
129, 11bitri 240 . . 3  |-  ( E. x ( x  e.  A  /\  <. x ,  y >.  e.  _I  ) 
<->  y  e.  A )
1312abbii 2408 . 2  |-  { y  |  E. x ( x  e.  A  /\  <.
x ,  y >.  e.  _I  ) }  =  { y  |  y  e.  A }
14 abid2 2413 . 2  |-  { y  |  y  e.  A }  =  A
151, 13, 143eqtri 2320 1  |-  (  _I  " A )  =  A
Colors of variables: wff set class
Syntax hints:    /\ wa 358   E.wex 1531    = wceq 1632    e. wcel 1696   {cab 2282   <.cop 3656   class class class wbr 4039    _I cid 4320   "cima 4708
This theorem is referenced by:  rnresi  5044  cnvresid  5338  ecidsn  6724  mbfid  19007
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-14 1700  ax-6 1715  ax-7 1720  ax-11 1727  ax-12 1878  ax-ext 2277  ax-sep 4157  ax-nul 4165  ax-pr 4230
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3an 936  df-tru 1310  df-ex 1532  df-nf 1535  df-sb 1639  df-eu 2160  df-mo 2161  df-clab 2283  df-cleq 2289  df-clel 2292  df-nfc 2421  df-ne 2461  df-ral 2561  df-rex 2562  df-rab 2565  df-v 2803  df-dif 3168  df-un 3170  df-in 3172  df-ss 3179  df-nul 3469  df-if 3579  df-sn 3659  df-pr 3660  df-op 3662  df-br 4040  df-opab 4094  df-id 4325  df-xp 4711  df-rel 4712  df-cnv 4713  df-dm 4715  df-rn 4716  df-res 4717  df-ima 4718
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