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Theorem limcdifap 15249
Description: It suffices to consider functions which are not defined at 
B to define the limit of a function. In particular, the value of the original function  F at  B does not affect the limit of  F. (Contributed by Mario Carneiro, 25-Dec-2016.) (Revised by Jim Kingdon, 3-Jun-2023.)
Hypotheses
Ref Expression
limccl.f  |-  ( ph  ->  F : A --> CC )
limcdifap.a  |-  ( ph  ->  A  C_  CC )
Assertion
Ref Expression
limcdifap  |-  ( ph  ->  ( F lim CC  B
)  =  ( ( F  |`  { x  e.  A  |  x #  B } ) lim CC  B
) )
Distinct variable groups:    x, A    x, B
Allowed substitution hints:    ph( x)    F( x)

Proof of Theorem limcdifap
Dummy variables  d  e  u  z are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 limcrcl 15245 . . . . 5  |-  ( u  e.  ( F lim CC  B )  ->  ( F : dom  F --> CC  /\  dom  F  C_  CC  /\  B  e.  CC ) )
21simp3d 1014 . . . 4  |-  ( u  e.  ( F lim CC  B )  ->  B  e.  CC )
32a1i 9 . . 3  |-  ( ph  ->  ( u  e.  ( F lim CC  B )  ->  B  e.  CC ) )
4 limcrcl 15245 . . . . 5  |-  ( u  e.  ( ( F  |`  { x  e.  A  |  x #  B }
) lim CC  B )  ->  ( ( F  |`  { x  e.  A  |  x #  B }
) : dom  ( F  |`  { x  e.  A  |  x #  B } ) --> CC  /\  dom  ( F  |`  { x  e.  A  |  x #  B } )  C_  CC  /\  B  e.  CC ) )
54simp3d 1014 . . . 4  |-  ( u  e.  ( ( F  |`  { x  e.  A  |  x #  B }
) lim CC  B )  ->  B  e.  CC )
65a1i 9 . . 3  |-  ( ph  ->  ( u  e.  ( ( F  |`  { x  e.  A  |  x #  B } ) lim CC  B
)  ->  B  e.  CC ) )
7 breq1 4062 . . . . . . . . . . . . . . . . 17  |-  ( x  =  z  ->  (
x #  B  <->  z #  B
) )
8 simplr 528 . . . . . . . . . . . . . . . . 17  |-  ( ( ( ( ph  /\  B  e.  CC )  /\  z  e.  A
)  /\  z #  B
)  ->  z  e.  A )
9 simpr 110 . . . . . . . . . . . . . . . . 17  |-  ( ( ( ( ph  /\  B  e.  CC )  /\  z  e.  A
)  /\  z #  B
)  ->  z #  B
)
107, 8, 9elrabd 2938 . . . . . . . . . . . . . . . 16  |-  ( ( ( ( ph  /\  B  e.  CC )  /\  z  e.  A
)  /\  z #  B
)  ->  z  e.  { x  e.  A  |  x #  B } )
11 fvres 5623 . . . . . . . . . . . . . . . . 17  |-  ( z  e.  { x  e.  A  |  x #  B }  ->  ( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  =  ( F `  z ) )
1211eqcomd 2213 . . . . . . . . . . . . . . . 16  |-  ( z  e.  { x  e.  A  |  x #  B }  ->  ( F `  z )  =  ( ( F  |`  { x  e.  A  |  x #  B } ) `  z
) )
1310, 12syl 14 . . . . . . . . . . . . . . 15  |-  ( ( ( ( ph  /\  B  e.  CC )  /\  z  e.  A
)  /\  z #  B
)  ->  ( F `  z )  =  ( ( F  |`  { x  e.  A  |  x #  B } ) `  z
) )
1413fvoveq1d 5989 . . . . . . . . . . . . . 14  |-  ( ( ( ( ph  /\  B  e.  CC )  /\  z  e.  A
)  /\  z #  B
)  ->  ( abs `  ( ( F `  z )  -  u
) )  =  ( abs `  ( ( ( F  |`  { x  e.  A  |  x #  B } ) `  z
)  -  u ) ) )
1514breq1d 4069 . . . . . . . . . . . . 13  |-  ( ( ( ( ph  /\  B  e.  CC )  /\  z  e.  A
)  /\  z #  B
)  ->  ( ( abs `  ( ( F `
 z )  -  u ) )  < 
e  <->  ( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) )
1615imbi2d 230 . . . . . . . . . . . 12  |-  ( ( ( ( ph  /\  B  e.  CC )  /\  z  e.  A
)  /\  z #  B
)  ->  ( (
( abs `  (
z  -  B ) )  <  d  -> 
( abs `  (
( F `  z
)  -  u ) )  <  e )  <-> 
( ( abs `  (
z  -  B ) )  <  d  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) )
1716pm5.74da 443 . . . . . . . . . . 11  |-  ( ( ( ph  /\  B  e.  CC )  /\  z  e.  A )  ->  (
( z #  B  -> 
( ( abs `  (
z  -  B ) )  <  d  -> 
( abs `  (
( F `  z
)  -  u ) )  <  e ) )  <->  ( z #  B  ->  ( ( abs `  (
z  -  B ) )  <  d  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) ) )
18 impexp 263 . . . . . . . . . . 11  |-  ( ( ( z #  B  /\  ( abs `  ( z  -  B ) )  <  d )  -> 
( abs `  (
( F `  z
)  -  u ) )  <  e )  <-> 
( z #  B  -> 
( ( abs `  (
z  -  B ) )  <  d  -> 
( abs `  (
( F `  z
)  -  u ) )  <  e ) ) )
19 impexp 263 . . . . . . . . . . . . 13  |-  ( ( ( z #  B  /\  ( abs `  ( z  -  B ) )  <  d )  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e )  <->  ( z #  B  ->  ( ( abs `  ( z  -  B
) )  <  d  ->  ( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) )
2019imbi2i 226 . . . . . . . . . . . 12  |-  ( ( z #  B  ->  (
( z #  B  /\  ( abs `  ( z  -  B ) )  <  d )  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) )  <->  ( z #  B  ->  ( z #  B  ->  ( ( abs `  (
z  -  B ) )  <  d  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) ) )
21 pm5.4 249 . . . . . . . . . . . 12  |-  ( ( z #  B  ->  (
z #  B  ->  (
( abs `  (
z  -  B ) )  <  d  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) )  <-> 
( z #  B  -> 
( ( abs `  (
z  -  B ) )  <  d  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) )
2220, 21bitri 184 . . . . . . . . . . 11  |-  ( ( z #  B  ->  (
( z #  B  /\  ( abs `  ( z  -  B ) )  <  d )  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) )  <->  ( z #  B  ->  ( ( abs `  ( z  -  B
) )  <  d  ->  ( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) )
2317, 18, 223bitr4g 223 . . . . . . . . . 10  |-  ( ( ( ph  /\  B  e.  CC )  /\  z  e.  A )  ->  (
( ( z #  B  /\  ( abs `  (
z  -  B ) )  <  d )  ->  ( abs `  (
( F `  z
)  -  u ) )  <  e )  <-> 
( z #  B  -> 
( ( z #  B  /\  ( abs `  (
z  -  B ) )  <  d )  ->  ( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) ) )
2423ralbidva 2504 . . . . . . . . 9  |-  ( (
ph  /\  B  e.  CC )  ->  ( A. z  e.  A  (
( z #  B  /\  ( abs `  ( z  -  B ) )  <  d )  -> 
( abs `  (
( F `  z
)  -  u ) )  <  e )  <->  A. z  e.  A  ( z #  B  ->  ( ( z #  B  /\  ( abs `  ( z  -  B ) )  <  d )  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) ) )
257ralrab 2941 . . . . . . . . 9  |-  ( A. z  e.  { x  e.  A  |  x #  B }  ( (
z #  B  /\  ( abs `  ( z  -  B ) )  < 
d )  ->  ( abs `  ( ( ( F  |`  { x  e.  A  |  x #  B } ) `  z
)  -  u ) )  <  e )  <->  A. z  e.  A  ( z #  B  ->  ( ( z #  B  /\  ( abs `  ( z  -  B ) )  <  d )  -> 
( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) )
2624, 25bitr4di 198 . . . . . . . 8  |-  ( (
ph  /\  B  e.  CC )  ->  ( A. z  e.  A  (
( z #  B  /\  ( abs `  ( z  -  B ) )  <  d )  -> 
( abs `  (
( F `  z
)  -  u ) )  <  e )  <->  A. z  e.  { x  e.  A  |  x #  B }  ( (
z #  B  /\  ( abs `  ( z  -  B ) )  < 
d )  ->  ( abs `  ( ( ( F  |`  { x  e.  A  |  x #  B } ) `  z
)  -  u ) )  <  e ) ) )
2726rexbidv 2509 . . . . . . 7  |-  ( (
ph  /\  B  e.  CC )  ->  ( E. d  e.  RR+  A. z  e.  A  ( (
z #  B  /\  ( abs `  ( z  -  B ) )  < 
d )  ->  ( abs `  ( ( F `
 z )  -  u ) )  < 
e )  <->  E. d  e.  RR+  A. z  e. 
{ x  e.  A  |  x #  B } 
( ( z #  B  /\  ( abs `  (
z  -  B ) )  <  d )  ->  ( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) )
2827ralbidv 2508 . . . . . 6  |-  ( (
ph  /\  B  e.  CC )  ->  ( A. e  e.  RR+  E. d  e.  RR+  A. z  e.  A  ( ( z #  B  /\  ( abs `  ( z  -  B
) )  <  d
)  ->  ( abs `  ( ( F `  z )  -  u
) )  <  e
)  <->  A. e  e.  RR+  E. d  e.  RR+  A. z  e.  { x  e.  A  |  x #  B } 
( ( z #  B  /\  ( abs `  (
z  -  B ) )  <  d )  ->  ( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) )
2928anbi2d 464 . . . . 5  |-  ( (
ph  /\  B  e.  CC )  ->  ( ( u  e.  CC  /\  A. e  e.  RR+  E. d  e.  RR+  A. z  e.  A  ( ( z #  B  /\  ( abs `  ( z  -  B
) )  <  d
)  ->  ( abs `  ( ( F `  z )  -  u
) )  <  e
) )  <->  ( u  e.  CC  /\  A. e  e.  RR+  E. d  e.  RR+  A. z  e.  {
x  e.  A  |  x #  B }  ( ( z #  B  /\  ( abs `  ( z  -  B ) )  < 
d )  ->  ( abs `  ( ( ( F  |`  { x  e.  A  |  x #  B } ) `  z
)  -  u ) )  <  e ) ) ) )
30 limccl.f . . . . . . 7  |-  ( ph  ->  F : A --> CC )
3130adantr 276 . . . . . 6  |-  ( (
ph  /\  B  e.  CC )  ->  F : A
--> CC )
32 limcdifap.a . . . . . . 7  |-  ( ph  ->  A  C_  CC )
3332adantr 276 . . . . . 6  |-  ( (
ph  /\  B  e.  CC )  ->  A  C_  CC )
34 simpr 110 . . . . . 6  |-  ( (
ph  /\  B  e.  CC )  ->  B  e.  CC )
3531, 33, 34ellimc3ap 15248 . . . . 5  |-  ( (
ph  /\  B  e.  CC )  ->  ( u  e.  ( F lim CC  B )  <->  ( u  e.  CC  /\  A. e  e.  RR+  E. d  e.  RR+  A. z  e.  A  ( ( z #  B  /\  ( abs `  (
z  -  B ) )  <  d )  ->  ( abs `  (
( F `  z
)  -  u ) )  <  e ) ) ) )
36 ssrab2 3286 . . . . . . 7  |-  { x  e.  A  |  x #  B }  C_  A
37 fssres 5473 . . . . . . 7  |-  ( ( F : A --> CC  /\  { x  e.  A  |  x #  B }  C_  A
)  ->  ( F  |` 
{ x  e.  A  |  x #  B }
) : { x  e.  A  |  x #  B } --> CC )
3831, 36, 37sylancl 413 . . . . . 6  |-  ( (
ph  /\  B  e.  CC )  ->  ( F  |`  { x  e.  A  |  x #  B }
) : { x  e.  A  |  x #  B } --> CC )
3936, 33sstrid 3212 . . . . . 6  |-  ( (
ph  /\  B  e.  CC )  ->  { x  e.  A  |  x #  B }  C_  CC )
4038, 39, 34ellimc3ap 15248 . . . . 5  |-  ( (
ph  /\  B  e.  CC )  ->  ( u  e.  ( ( F  |`  { x  e.  A  |  x #  B }
) lim CC  B )  <->  ( u  e.  CC  /\  A. e  e.  RR+  E. d  e.  RR+  A. z  e. 
{ x  e.  A  |  x #  B } 
( ( z #  B  /\  ( abs `  (
z  -  B ) )  <  d )  ->  ( abs `  (
( ( F  |`  { x  e.  A  |  x #  B }
) `  z )  -  u ) )  < 
e ) ) ) )
4129, 35, 403bitr4d 220 . . . 4  |-  ( (
ph  /\  B  e.  CC )  ->  ( u  e.  ( F lim CC  B )  <->  u  e.  ( ( F  |`  { x  e.  A  |  x #  B }
) lim CC  B )
) )
4241ex 115 . . 3  |-  ( ph  ->  ( B  e.  CC  ->  ( u  e.  ( F lim CC  B )  <-> 
u  e.  ( ( F  |`  { x  e.  A  |  x #  B } ) lim CC  B
) ) ) )
433, 6, 42pm5.21ndd 707 . 2  |-  ( ph  ->  ( u  e.  ( F lim CC  B )  <-> 
u  e.  ( ( F  |`  { x  e.  A  |  x #  B } ) lim CC  B
) ) )
4443eqrdv 2205 1  |-  ( ph  ->  ( F lim CC  B
)  =  ( ( F  |`  { x  e.  A  |  x #  B } ) lim CC  B
) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 104    <-> wb 105    = wceq 1373    e. wcel 2178   A.wral 2486   E.wrex 2487   {crab 2490    C_ wss 3174   class class class wbr 4059   dom cdm 4693    |` cres 4695   -->wf 5286   ` cfv 5290  (class class class)co 5967   CCcc 7958    < clt 8142    - cmin 8278   # cap 8689   RR+crp 9810   abscabs 11423   lim CC climc 15241
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 615  ax-in2 616  ax-io 711  ax-5 1471  ax-7 1472  ax-gen 1473  ax-ie1 1517  ax-ie2 1518  ax-8 1528  ax-10 1529  ax-11 1530  ax-i12 1531  ax-bndl 1533  ax-4 1534  ax-17 1550  ax-i9 1554  ax-ial 1558  ax-i5r 1559  ax-13 2180  ax-14 2181  ax-ext 2189  ax-sep 4178  ax-pow 4234  ax-pr 4269  ax-un 4498  ax-setind 4603  ax-cnex 8051
This theorem depends on definitions:  df-bi 117  df-3an 983  df-tru 1376  df-fal 1379  df-nf 1485  df-sb 1787  df-eu 2058  df-mo 2059  df-clab 2194  df-cleq 2200  df-clel 2203  df-nfc 2339  df-ne 2379  df-ral 2491  df-rex 2492  df-rab 2495  df-v 2778  df-sbc 3006  df-dif 3176  df-un 3178  df-in 3180  df-ss 3187  df-pw 3628  df-sn 3649  df-pr 3650  df-op 3652  df-uni 3865  df-br 4060  df-opab 4122  df-id 4358  df-xp 4699  df-rel 4700  df-cnv 4701  df-co 4702  df-dm 4703  df-rn 4704  df-res 4705  df-iota 5251  df-fun 5292  df-fn 5293  df-f 5294  df-fv 5298  df-ov 5970  df-oprab 5971  df-mpo 5972  df-pm 6761  df-limced 15243
This theorem is referenced by:  dvcnp2cntop  15286  dvmulxxbr  15289  dvrecap  15300
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