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Theorem xaddf 12055
Description: The extended real addition operation is closed in extended reals. (Contributed by Mario Carneiro, 21-Aug-2015.)
Assertion
Ref Expression
xaddf  |-  +e : ( RR*  X.  RR* )
--> RR*

Proof of Theorem xaddf
Dummy variables  x  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 0xr 10086 . . . . . 6  |-  0  e.  RR*
2 pnfxr 10092 . . . . . 6  |- +oo  e.  RR*
31, 2keepel 4155 . . . . 5  |-  if ( y  = -oo , 
0 , +oo )  e.  RR*
43a1i 11 . . . 4  |-  ( ( ( x  e.  RR*  /\  y  e.  RR* )  /\  x  = +oo )  ->  if ( y  = -oo ,  0 , +oo )  e. 
RR* )
5 mnfxr 10096 . . . . . . 7  |- -oo  e.  RR*
61, 5keepel 4155 . . . . . 6  |-  if ( y  = +oo , 
0 , -oo )  e.  RR*
76a1i 11 . . . . 5  |-  ( ( ( ( x  e. 
RR*  /\  y  e.  RR* )  /\  -.  x  = +oo )  /\  x  = -oo )  ->  if ( y  = +oo ,  0 , -oo )  e.  RR* )
82a1i 11 . . . . . . . 8  |-  ( ( ( ( x  e. 
RR*  /\  ( -.  x  = +oo  /\  -.  x  = -oo )
)  /\  y  e.  RR* )  /\  y  = +oo )  -> +oo  e.  RR* )
95a1i 11 . . . . . . . . 9  |-  ( ( ( ( ( x  e.  RR*  /\  ( -.  x  = +oo  /\ 
-.  x  = -oo ) )  /\  y  e.  RR* )  /\  -.  y  = +oo )  /\  y  = -oo )  -> -oo  e.  RR* )
10 ioran 511 . . . . . . . . . . . . . 14  |-  ( -.  ( x  = +oo  \/  x  = -oo ) 
<->  ( -.  x  = +oo  /\  -.  x  = -oo ) )
11 elxr 11950 . . . . . . . . . . . . . . . . . 18  |-  ( x  e.  RR*  <->  ( x  e.  RR  \/  x  = +oo  \/  x  = -oo ) )
12 3orass 1040 . . . . . . . . . . . . . . . . . 18  |-  ( ( x  e.  RR  \/  x  = +oo  \/  x  = -oo )  <->  ( x  e.  RR  \/  ( x  = +oo  \/  x  = -oo ) ) )
1311, 12sylbb 209 . . . . . . . . . . . . . . . . 17  |-  ( x  e.  RR*  ->  ( x  e.  RR  \/  (
x  = +oo  \/  x  = -oo )
) )
1413ord 392 . . . . . . . . . . . . . . . 16  |-  ( x  e.  RR*  ->  ( -.  x  e.  RR  ->  ( x  = +oo  \/  x  = -oo )
) )
1514con1d 139 . . . . . . . . . . . . . . 15  |-  ( x  e.  RR*  ->  ( -.  ( x  = +oo  \/  x  = -oo )  ->  x  e.  RR ) )
1615imp 445 . . . . . . . . . . . . . 14  |-  ( ( x  e.  RR*  /\  -.  ( x  = +oo  \/  x  = -oo ) )  ->  x  e.  RR )
1710, 16sylan2br 493 . . . . . . . . . . . . 13  |-  ( ( x  e.  RR*  /\  ( -.  x  = +oo  /\ 
-.  x  = -oo ) )  ->  x  e.  RR )
18 ioran 511 . . . . . . . . . . . . . 14  |-  ( -.  ( y  = +oo  \/  y  = -oo ) 
<->  ( -.  y  = +oo  /\  -.  y  = -oo ) )
19 elxr 11950 . . . . . . . . . . . . . . . . . 18  |-  ( y  e.  RR*  <->  ( y  e.  RR  \/  y  = +oo  \/  y  = -oo ) )
20 3orass 1040 . . . . . . . . . . . . . . . . . 18  |-  ( ( y  e.  RR  \/  y  = +oo  \/  y  = -oo )  <->  ( y  e.  RR  \/  ( y  = +oo  \/  y  = -oo ) ) )
2119, 20sylbb 209 . . . . . . . . . . . . . . . . 17  |-  ( y  e.  RR*  ->  ( y  e.  RR  \/  (
y  = +oo  \/  y  = -oo )
) )
2221ord 392 . . . . . . . . . . . . . . . 16  |-  ( y  e.  RR*  ->  ( -.  y  e.  RR  ->  ( y  = +oo  \/  y  = -oo )
) )
2322con1d 139 . . . . . . . . . . . . . . 15  |-  ( y  e.  RR*  ->  ( -.  ( y  = +oo  \/  y  = -oo )  ->  y  e.  RR ) )
2423imp 445 . . . . . . . . . . . . . 14  |-  ( ( y  e.  RR*  /\  -.  ( y  = +oo  \/  y  = -oo ) )  ->  y  e.  RR )
2518, 24sylan2br 493 . . . . . . . . . . . . 13  |-  ( ( y  e.  RR*  /\  ( -.  y  = +oo  /\ 
-.  y  = -oo ) )  ->  y  e.  RR )
26 readdcl 10019 . . . . . . . . . . . . 13  |-  ( ( x  e.  RR  /\  y  e.  RR )  ->  ( x  +  y )  e.  RR )
2717, 25, 26syl2an 494 . . . . . . . . . . . 12  |-  ( ( ( x  e.  RR*  /\  ( -.  x  = +oo  /\  -.  x  = -oo ) )  /\  ( y  e.  RR*  /\  ( -.  y  = +oo  /\  -.  y  = -oo ) ) )  ->  ( x  +  y )  e.  RR )
2827rexrd 10089 . . . . . . . . . . 11  |-  ( ( ( x  e.  RR*  /\  ( -.  x  = +oo  /\  -.  x  = -oo ) )  /\  ( y  e.  RR*  /\  ( -.  y  = +oo  /\  -.  y  = -oo ) ) )  ->  ( x  +  y )  e.  RR* )
2928anassrs 680 . . . . . . . . . 10  |-  ( ( ( ( x  e. 
RR*  /\  ( -.  x  = +oo  /\  -.  x  = -oo )
)  /\  y  e.  RR* )  /\  ( -.  y  = +oo  /\  -.  y  = -oo ) )  ->  (
x  +  y )  e.  RR* )
3029anassrs 680 . . . . . . . . 9  |-  ( ( ( ( ( x  e.  RR*  /\  ( -.  x  = +oo  /\ 
-.  x  = -oo ) )  /\  y  e.  RR* )  /\  -.  y  = +oo )  /\  -.  y  = -oo )  ->  ( x  +  y )  e.  RR* )
319, 30ifclda 4120 . . . . . . . 8  |-  ( ( ( ( x  e. 
RR*  /\  ( -.  x  = +oo  /\  -.  x  = -oo )
)  /\  y  e.  RR* )  /\  -.  y  = +oo )  ->  if ( y  = -oo , -oo ,  ( x  +  y ) )  e.  RR* )
328, 31ifclda 4120 . . . . . . 7  |-  ( ( ( x  e.  RR*  /\  ( -.  x  = +oo  /\  -.  x  = -oo ) )  /\  y  e.  RR* )  ->  if ( y  = +oo , +oo ,  if ( y  = -oo , -oo ,  ( x  +  y ) ) )  e.  RR* )
3332an32s 846 . . . . . 6  |-  ( ( ( x  e.  RR*  /\  y  e.  RR* )  /\  ( -.  x  = +oo  /\  -.  x  = -oo ) )  ->  if ( y  = +oo , +oo ,  if ( y  = -oo , -oo ,  ( x  +  y ) ) )  e.  RR* )
3433anassrs 680 . . . . 5  |-  ( ( ( ( x  e. 
RR*  /\  y  e.  RR* )  /\  -.  x  = +oo )  /\  -.  x  = -oo )  ->  if ( y  = +oo , +oo ,  if ( y  = -oo , -oo ,  ( x  +  y ) ) )  e.  RR* )
357, 34ifclda 4120 . . . 4  |-  ( ( ( x  e.  RR*  /\  y  e.  RR* )  /\  -.  x  = +oo )  ->  if ( x  = -oo ,  if ( y  = +oo ,  0 , -oo ) ,  if (
y  = +oo , +oo ,  if ( y  = -oo , -oo ,  ( x  +  y ) ) ) )  e.  RR* )
364, 35ifclda 4120 . . 3  |-  ( ( x  e.  RR*  /\  y  e.  RR* )  ->  if ( x  = +oo ,  if ( y  = -oo ,  0 , +oo ) ,  if ( x  = -oo ,  if ( y  = +oo ,  0 , -oo ) ,  if ( y  = +oo , +oo ,  if ( y  = -oo , -oo ,  ( x  +  y ) ) ) ) )  e.  RR* )
3736rgen2a 2977 . 2  |-  A. x  e.  RR*  A. y  e. 
RR*  if ( x  = +oo ,  if ( y  = -oo , 
0 , +oo ) ,  if ( x  = -oo ,  if ( y  = +oo , 
0 , -oo ) ,  if ( y  = +oo , +oo ,  if ( y  = -oo , -oo ,  ( x  +  y ) ) ) ) )  e. 
RR*
38 df-xadd 11947 . . 3  |-  +e 
=  ( x  e. 
RR* ,  y  e.  RR*  |->  if ( x  = +oo ,  if ( y  = -oo , 
0 , +oo ) ,  if ( x  = -oo ,  if ( y  = +oo , 
0 , -oo ) ,  if ( y  = +oo , +oo ,  if ( y  = -oo , -oo ,  ( x  +  y ) ) ) ) ) )
3938fmpt2 7237 . 2  |-  ( A. x  e.  RR*  A. y  e.  RR*  if ( x  = +oo ,  if ( y  = -oo ,  0 , +oo ) ,  if (
x  = -oo ,  if ( y  = +oo ,  0 , -oo ) ,  if (
y  = +oo , +oo ,  if ( y  = -oo , -oo ,  ( x  +  y ) ) ) ) )  e.  RR*  <->  +e : ( RR*  X.  RR* )
--> RR* )
4037, 39mpbi 220 1  |-  +e : ( RR*  X.  RR* )
--> RR*
Colors of variables: wff setvar class
Syntax hints:   -. wn 3    \/ wo 383    /\ wa 384    \/ w3o 1036    = wceq 1483    e. wcel 1990   A.wral 2912   ifcif 4086    X. cxp 5112   -->wf 5884  (class class class)co 6650   RRcr 9935   0cc0 9936    + caddc 9939   +oocpnf 10071   -oocmnf 10072   RR*cxr 10073   +ecxad 11944
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949  ax-cnex 9992  ax-1cn 9994  ax-icn 9995  ax-addcl 9996  ax-addrcl 9997  ax-mulcl 9998  ax-mulrcl 9999  ax-i2m1 10004  ax-1ne0 10005  ax-rnegex 10007  ax-rrecex 10008  ax-cnre 10009
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1038  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-ral 2917  df-rex 2918  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-op 4184  df-uni 4437  df-iun 4522  df-br 4654  df-opab 4713  df-mpt 4730  df-id 5024  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-iota 5851  df-fun 5890  df-fn 5891  df-f 5892  df-fv 5896  df-ov 6653  df-oprab 6654  df-mpt2 6655  df-1st 7168  df-2nd 7169  df-pnf 10076  df-mnf 10077  df-xr 10078  df-xadd 11947
This theorem is referenced by:  xaddcl  12070  xrsadd  19763  xrofsup  29533  xrge0pluscn  29986  xrge0tmdOLD  29991
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