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Theorem xrre 9528
Description: A way of proving that an extended real is real. (Contributed by NM, 9-Mar-2006.)
Assertion
Ref Expression
xrre  |-  ( ( ( A  e.  RR*  /\  B  e.  RR )  /\  (  -oo  <  A  /\  A  <_  B
) )  ->  A  e.  RR )

Proof of Theorem xrre
StepHypRef Expression
1 simprl 707 . 2  |-  ( ( ( A  e.  RR*  /\  B  e.  RR )  /\  (  -oo  <  A  /\  A  <_  B
) )  ->  -oo  <  A )
2 ltpnf 9493 . . . . . 6  |-  ( B  e.  RR  ->  B  <  +oo )
32adantl 445 . . . . 5  |-  ( ( A  e.  RR*  /\  B  e.  RR )  ->  B  <  +oo )
4 rexr 8279 . . . . . 6  |-  ( B  e.  RR  ->  B  e.  RR* )
5 pnfxr 9485 . . . . . . 7  |-  +oo  e.  RR*
6 xrlelttr 9517 . . . . . . 7  |-  ( ( A  e.  RR*  /\  B  e.  RR*  /\  +oo  e.  RR* )  ->  ( ( A  <_  B  /\  B  <  +oo )  ->  A  <  +oo ) )
75, 6mp3an3 1222 . . . . . 6  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A  <_  B  /\  B  <  +oo )  ->  A  <  +oo )
)
84, 7sylan2 453 . . . . 5  |-  ( ( A  e.  RR*  /\  B  e.  RR )  ->  (
( A  <_  B  /\  B  <  +oo )  ->  A  <  +oo )
)
93, 8mpan2d 647 . . . 4  |-  ( ( A  e.  RR*  /\  B  e.  RR )  ->  ( A  <_  B  ->  A  <  +oo ) )
109imp 414 . . 3  |-  ( ( ( A  e.  RR*  /\  B  e.  RR )  /\  A  <_  B
)  ->  A  <  +oo )
1110adantrl 686 . 2  |-  ( ( ( A  e.  RR*  /\  B  e.  RR )  /\  (  -oo  <  A  /\  A  <_  B
) )  ->  A  <  +oo )
12 xrrebnd 9527 . . 3  |-  ( A  e.  RR*  ->  ( A  e.  RR  <->  (  -oo  <  A  /\  A  <  +oo ) ) )
1312ad2antrr 696 . 2  |-  ( ( ( A  e.  RR*  /\  B  e.  RR )  /\  (  -oo  <  A  /\  A  <_  B
) )  ->  ( A  e.  RR  <->  (  -oo  <  A  /\  A  <  +oo ) ) )
141, 11, 13mpbir2and 848 1  |-  ( ( ( A  e.  RR*  /\  B  e.  RR )  /\  (  -oo  <  A  /\  A  <_  B
) )  ->  A  e.  RR )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 174    /\ wa 356    e. wcel 1520   class class class wbr 3584   RRcr 8152    <_ cle 8266    +oocpnf 8267    -oocmnf 8268   RR*cxr 8269    < clt 8270
This theorem is referenced by:  xrrege0  9532  supxrre  9672  infmxrre  9680  caucvgrlem  10816  pcgcd1  11500  tgioo  16453  ovolunlem1a  16997  ovoliunlem1  17003  ioombl1lem2  17058  itg2monolem2  17248  dvferm1lem  17443  radcnvle  17826  psercnlem1  17831  nmobndi  19176  ubthlem3  19274  nmophmi  20434  bdophsi  20499  bdopcoi  20501
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-5 1440  ax-6 1441  ax-7 1442  ax-gen 1443  ax-8 1522  ax-11 1523  ax-13 1524  ax-14 1525  ax-17 1527  ax-12o 1560  ax-10 1574  ax-9 1580  ax-4 1587  ax-16 1773  ax-ext 2044  ax-sep 3699  ax-nul 3707  ax-pow 3743  ax-pr 3767  ax-un 4059  ax-cnex 8208  ax-resscn 8209  ax-pre-lttri 8226  ax-pre-lttrn 8227
This theorem depends on definitions:  df-bi 175  df-or 357  df-an 358  df-3or 895  df-3an 896  df-tru 1257  df-ex 1445  df-sb 1734  df-eu 1956  df-mo 1957  df-clab 2050  df-cleq 2055  df-clel 2058  df-ne 2182  df-nel 2183  df-ral 2276  df-rex 2277  df-rab 2279  df-v 2475  df-sbc 2649  df-csb 2731  df-dif 2794  df-un 2796  df-in 2798  df-ss 2802  df-nul 3071  df-if 3180  df-pw 3241  df-sn 3259  df-pr 3260  df-op 3262  df-uni 3423  df-br 3585  df-opab 3639  df-mpt 3640  df-id 3858  df-po 3863  df-so 3864  df-xp 4268  df-rel 4269  df-cnv 4270  df-co 4271  df-dm 4272  df-rn 4273  df-res 4274  df-ima 4275  df-fun 4276  df-fn 4277  df-f 4278  df-f1 4279  df-fo 4280  df-f1o 4281  df-fv 4282  df-er 6111  df-en 6298  df-dom 6299  df-sdom 6300  df-pnf 8271  df-mnf 8272  df-xr 8273  df-ltxr 8274  df-le 8275
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