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Theorem mpt20 6215
Description: A mapping operation with empty domain. (Contributed by Stefan O'Rear, 29-Jan-2015.) (Revised by Mario Carneiro, 15-May-2015.)
Assertion
Ref Expression
mpt20  |-  ( x  e.  (/) ,  y  e.  B  |->  C )  =  (/)

Proof of Theorem mpt20
Dummy variables  w  z are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 df-mpt2 5879 . 2  |-  ( x  e.  (/) ,  y  e.  B  |->  C )  =  { <. <. x ,  y
>. ,  z >.  |  ( ( x  e.  (/)  /\  y  e.  B
)  /\  z  =  C ) }
2 df-oprab 5878 . 2  |-  { <. <.
x ,  y >. ,  z >.  |  ( ( x  e.  (/)  /\  y  e.  B )  /\  z  =  C ) }  =  {
w  |  E. x E. y E. z ( w  =  <. <. x ,  y >. ,  z
>.  /\  ( ( x  e.  (/)  /\  y  e.  B )  /\  z  =  C ) ) }
3 noel 3472 . . . . . . 7  |-  -.  x  e.  (/)
4 simprll 738 . . . . . . 7  |-  ( ( w  =  <. <. x ,  y >. ,  z
>.  /\  ( ( x  e.  (/)  /\  y  e.  B )  /\  z  =  C ) )  ->  x  e.  (/) )
53, 4mto 167 . . . . . 6  |-  -.  (
w  =  <. <. x ,  y >. ,  z
>.  /\  ( ( x  e.  (/)  /\  y  e.  B )  /\  z  =  C ) )
65nex 1545 . . . . 5  |-  -.  E. z ( w  = 
<. <. x ,  y
>. ,  z >.  /\  ( ( x  e.  (/)  /\  y  e.  B
)  /\  z  =  C ) )
76nex 1545 . . . 4  |-  -.  E. y E. z ( w  =  <. <. x ,  y
>. ,  z >.  /\  ( ( x  e.  (/)  /\  y  e.  B
)  /\  z  =  C ) )
87nex 1545 . . 3  |-  -.  E. x E. y E. z
( w  =  <. <.
x ,  y >. ,  z >.  /\  (
( x  e.  (/)  /\  y  e.  B )  /\  z  =  C ) )
98abf 3501 . 2  |-  { w  |  E. x E. y E. z ( w  = 
<. <. x ,  y
>. ,  z >.  /\  ( ( x  e.  (/)  /\  y  e.  B
)  /\  z  =  C ) ) }  =  (/)
101, 2, 93eqtri 2320 1  |-  ( x  e.  (/) ,  y  e.  B  |->  C )  =  (/)
Colors of variables: wff set class
Syntax hints:    /\ wa 358   E.wex 1531    = wceq 1632    e. wcel 1696   {cab 2282   (/)c0 3468   <.cop 3656   {coprab 5875    e. cmpt2 5876
This theorem is referenced by:  homffval  13610  comfffval  13617  natfval  13836  coafval  13912  xpchomfval  13969  xpccofval  13972  meet0  14257  join0  14258  plusffval  14395  grpsubfval  14540  oppglsm  14969  dvrfval  15482  scaffval  15661  psrmulr  16145  ipffval  16568  pcofval  18524  mendplusgfval  27596  mendmulrfval  27598  mendvscafval  27601
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-dif 3168  df-in 3172  df-ss 3179  df-nul 3469  df-oprab 5878  df-mpt2 5879
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