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Theorem ltxr 9897
Description: The 'less than' binary relation on the set of extended reals. Definition 12-3.1 of [Gleason] p. 173. (Contributed by NM, 14-Oct-2005.)
Assertion
Ref Expression
ltxr  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( A  <  B  <->  ( (
( ( A  e.  RR  /\  B  e.  RR )  /\  A  <RR  B )  \/  ( A  = -oo  /\  B  = +oo ) )  \/  ( ( A  e.  RR  /\  B  = +oo )  \/  ( A  = -oo  /\  B  e.  RR ) ) ) ) )

Proof of Theorem ltxr
Dummy variables  x  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 breq12 4049 . . . . 5  |-  ( ( x  =  A  /\  y  =  B )  ->  ( x  <RR  y  <->  A  <RR  B ) )
2 df-3an 983 . . . . . 6  |-  ( ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y )  <->  ( (
x  e.  RR  /\  y  e.  RR )  /\  x  <RR  y ) )
32opabbii 4111 . . . . 5  |-  { <. x ,  y >.  |  ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y ) }  =  { <. x ,  y
>.  |  ( (
x  e.  RR  /\  y  e.  RR )  /\  x  <RR  y ) }
41, 3brab2ga 4750 . . . 4  |-  ( A { <. x ,  y
>.  |  ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y ) } B  <->  ( ( A  e.  RR  /\  B  e.  RR )  /\  A  <RR  B ) )
54a1i 9 . . 3  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( A { <. x ,  y
>.  |  ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y ) } B  <->  ( ( A  e.  RR  /\  B  e.  RR )  /\  A  <RR  B ) ) )
6 brun 4095 . . . 4  |-  ( A ( ( ( RR  u.  { -oo }
)  X.  { +oo } )  u.  ( { -oo }  X.  RR ) ) B  <->  ( A
( ( RR  u.  { -oo } )  X. 
{ +oo } ) B  \/  A ( { -oo }  X.  RR ) B ) )
7 brxp 4706 . . . . . . 7  |-  ( A ( ( RR  u.  { -oo } )  X. 
{ +oo } ) B  <-> 
( A  e.  ( RR  u.  { -oo } )  /\  B  e. 
{ +oo } ) )
8 elun 3314 . . . . . . . . . . 11  |-  ( A  e.  ( RR  u.  { -oo } )  <->  ( A  e.  RR  \/  A  e. 
{ -oo } ) )
9 orcom 730 . . . . . . . . . . 11  |-  ( ( A  e.  RR  \/  A  e.  { -oo }
)  <->  ( A  e. 
{ -oo }  \/  A  e.  RR ) )
108, 9bitri 184 . . . . . . . . . 10  |-  ( A  e.  ( RR  u.  { -oo } )  <->  ( A  e.  { -oo }  \/  A  e.  RR )
)
11 elsng 3648 . . . . . . . . . . 11  |-  ( A  e.  RR*  ->  ( A  e.  { -oo }  <->  A  = -oo ) )
1211orbi1d 793 . . . . . . . . . 10  |-  ( A  e.  RR*  ->  ( ( A  e.  { -oo }  \/  A  e.  RR ) 
<->  ( A  = -oo  \/  A  e.  RR ) ) )
1310, 12bitrid 192 . . . . . . . . 9  |-  ( A  e.  RR*  ->  ( A  e.  ( RR  u.  { -oo } )  <->  ( A  = -oo  \/  A  e.  RR ) ) )
14 elsng 3648 . . . . . . . . 9  |-  ( B  e.  RR*  ->  ( B  e.  { +oo }  <->  B  = +oo ) )
1513, 14bi2anan9 606 . . . . . . . 8  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A  e.  ( RR  u.  { -oo } )  /\  B  e. 
{ +oo } )  <->  ( ( A  = -oo  \/  A  e.  RR )  /\  B  = +oo ) ) )
16 andir 821 . . . . . . . 8  |-  ( ( ( A  = -oo  \/  A  e.  RR )  /\  B  = +oo ) 
<->  ( ( A  = -oo  /\  B  = +oo )  \/  ( A  e.  RR  /\  B  = +oo ) ) )
1715, 16bitrdi 196 . . . . . . 7  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A  e.  ( RR  u.  { -oo } )  /\  B  e. 
{ +oo } )  <->  ( ( A  = -oo  /\  B  = +oo )  \/  ( A  e.  RR  /\  B  = +oo ) ) ) )
187, 17bitrid 192 . . . . . 6  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( A ( ( RR  u.  { -oo }
)  X.  { +oo } ) B  <->  ( ( A  = -oo  /\  B  = +oo )  \/  ( A  e.  RR  /\  B  = +oo ) ) ) )
19 brxp 4706 . . . . . . 7  |-  ( A ( { -oo }  X.  RR ) B  <->  ( A  e.  { -oo }  /\  B  e.  RR )
)
2011anbi1d 465 . . . . . . . 8  |-  ( A  e.  RR*  ->  ( ( A  e.  { -oo }  /\  B  e.  RR ) 
<->  ( A  = -oo  /\  B  e.  RR ) ) )
2120adantr 276 . . . . . . 7  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A  e.  { -oo }  /\  B  e.  RR )  <->  ( A  = -oo  /\  B  e.  RR ) ) )
2219, 21bitrid 192 . . . . . 6  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( A ( { -oo }  X.  RR ) B  <-> 
( A  = -oo  /\  B  e.  RR ) ) )
2318, 22orbi12d 795 . . . . 5  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A ( ( RR  u.  { -oo } )  X.  { +oo } ) B  \/  A
( { -oo }  X.  RR ) B )  <-> 
( ( ( A  = -oo  /\  B  = +oo )  \/  ( A  e.  RR  /\  B  = +oo ) )  \/  ( A  = -oo  /\  B  e.  RR ) ) ) )
24 orass 769 . . . . 5  |-  ( ( ( ( A  = -oo  /\  B  = +oo )  \/  ( A  e.  RR  /\  B  = +oo ) )  \/  ( A  = -oo  /\  B  e.  RR ) )  <->  ( ( A  = -oo  /\  B  = +oo )  \/  (
( A  e.  RR  /\  B  = +oo )  \/  ( A  = -oo  /\  B  e.  RR ) ) ) )
2523, 24bitrdi 196 . . . 4  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A ( ( RR  u.  { -oo } )  X.  { +oo } ) B  \/  A
( { -oo }  X.  RR ) B )  <-> 
( ( A  = -oo  /\  B  = +oo )  \/  (
( A  e.  RR  /\  B  = +oo )  \/  ( A  = -oo  /\  B  e.  RR ) ) ) ) )
266, 25bitrid 192 . . 3  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( A ( ( ( RR  u.  { -oo } )  X.  { +oo } )  u.  ( { -oo }  X.  RR ) ) B  <->  ( ( A  = -oo  /\  B  = +oo )  \/  (
( A  e.  RR  /\  B  = +oo )  \/  ( A  = -oo  /\  B  e.  RR ) ) ) ) )
275, 26orbi12d 795 . 2  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A { <. x ,  y >.  |  ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y ) } B  \/  A ( ( ( RR  u.  { -oo } )  X.  { +oo } )  u.  ( { -oo }  X.  RR ) ) B )  <-> 
( ( ( A  e.  RR  /\  B  e.  RR )  /\  A  <RR  B )  \/  (
( A  = -oo  /\  B  = +oo )  \/  ( ( A  e.  RR  /\  B  = +oo )  \/  ( A  = -oo  /\  B  e.  RR ) ) ) ) ) )
28 df-ltxr 8112 . . . 4  |-  <  =  ( { <. x ,  y
>.  |  ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y ) }  u.  (
( ( RR  u.  { -oo } )  X. 
{ +oo } )  u.  ( { -oo }  X.  RR ) ) )
2928breqi 4050 . . 3  |-  ( A  <  B  <->  A ( { <. x ,  y
>.  |  ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y ) }  u.  (
( ( RR  u.  { -oo } )  X. 
{ +oo } )  u.  ( { -oo }  X.  RR ) ) ) B )
30 brun 4095 . . 3  |-  ( A ( { <. x ,  y >.  |  ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y ) }  u.  ( ( ( RR  u.  { -oo }
)  X.  { +oo } )  u.  ( { -oo }  X.  RR ) ) ) B  <-> 
( A { <. x ,  y >.  |  ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y ) } B  \/  A ( ( ( RR  u.  { -oo } )  X.  { +oo } )  u.  ( { -oo }  X.  RR ) ) B ) )
3129, 30bitri 184 . 2  |-  ( A  <  B  <->  ( A { <. x ,  y
>.  |  ( x  e.  RR  /\  y  e.  RR  /\  x  <RR  y ) } B  \/  A ( ( ( RR  u.  { -oo } )  X.  { +oo } )  u.  ( { -oo }  X.  RR ) ) B ) )
32 orass 769 . 2  |-  ( ( ( ( ( A  e.  RR  /\  B  e.  RR )  /\  A  <RR  B )  \/  ( A  = -oo  /\  B  = +oo ) )  \/  ( ( A  e.  RR  /\  B  = +oo )  \/  ( A  = -oo  /\  B  e.  RR ) ) )  <-> 
( ( ( A  e.  RR  /\  B  e.  RR )  /\  A  <RR  B )  \/  (
( A  = -oo  /\  B  = +oo )  \/  ( ( A  e.  RR  /\  B  = +oo )  \/  ( A  = -oo  /\  B  e.  RR ) ) ) ) )
3327, 31, 323bitr4g 223 1  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( A  <  B  <->  ( (
( ( A  e.  RR  /\  B  e.  RR )  /\  A  <RR  B )  \/  ( A  = -oo  /\  B  = +oo ) )  \/  ( ( A  e.  RR  /\  B  = +oo )  \/  ( A  = -oo  /\  B  e.  RR ) ) ) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 104    <-> wb 105    \/ wo 710    /\ w3a 981    = wceq 1373    e. wcel 2176    u. cun 3164   {csn 3633   class class class wbr 4044   {copab 4104    X. cxp 4673   RRcr 7924    <RR cltrr 7929   +oocpnf 8104   -oocmnf 8105   RR*cxr 8106    < clt 8107
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-io 711  ax-5 1470  ax-7 1471  ax-gen 1472  ax-ie1 1516  ax-ie2 1517  ax-8 1527  ax-10 1528  ax-11 1529  ax-i12 1530  ax-bndl 1532  ax-4 1533  ax-17 1549  ax-i9 1553  ax-ial 1557  ax-i5r 1558  ax-14 2179  ax-ext 2187  ax-sep 4162  ax-pow 4218  ax-pr 4253
This theorem depends on definitions:  df-bi 117  df-3an 983  df-tru 1376  df-nf 1484  df-sb 1786  df-eu 2057  df-mo 2058  df-clab 2192  df-cleq 2198  df-clel 2201  df-nfc 2337  df-ral 2489  df-rex 2490  df-v 2774  df-un 3170  df-in 3172  df-ss 3179  df-pw 3618  df-sn 3639  df-pr 3640  df-op 3642  df-br 4045  df-opab 4106  df-xp 4681  df-ltxr 8112
This theorem is referenced by:  xrltnr  9901  ltpnf  9902  mnflt  9905  mnfltpnf  9907  pnfnlt  9909  nltmnf  9910
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