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Theorem ioo0 9707
Description: An empty open interval of extended reals. (Contributed by NM, 6-Feb-2007.)
Assertion
Ref Expression
ioo0  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A (,) B
)  =  (/)  <->  B  <_  A ) )

Proof of Theorem ioo0
StepHypRef Expression
1 iooval 9706 . . 3  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( A (,) B )  =  { x  e.  RR*  |  ( A  <  x  /\  x  <  B ) } )
21eqeq1d 2070 . 2  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A (,) B
)  =  (/)  <->  { x  e.  RR*  |  ( A  <  x  /\  x  <  B ) }  =  (/) ) )
3 df-ne 2182 . . . . . 6  |-  ( { x  e.  RR*  |  ( A  <  x  /\  x  <  B ) }  =/=  (/)  <->  -.  { x  e.  RR*  |  ( A  <  x  /\  x  <  B ) }  =  (/) )
4 rabn0 3089 . . . . . 6  |-  ( { x  e.  RR*  |  ( A  <  x  /\  x  <  B ) }  =/=  (/)  <->  E. x  e.  RR*  ( A  <  x  /\  x  <  B ) )
53, 4bitr3i 240 . . . . 5  |-  ( -. 
{ x  e.  RR*  |  ( A  <  x  /\  x  <  B ) }  =  (/)  <->  E. x  e.  RR*  ( A  < 
x  /\  x  <  B ) )
6 xrlttr 9504 . . . . . . . . 9  |-  ( ( A  e.  RR*  /\  x  e.  RR*  /\  B  e. 
RR* )  ->  (
( A  <  x  /\  x  <  B )  ->  A  <  B
) )
763com23 1114 . . . . . . . 8  |-  ( ( A  e.  RR*  /\  B  e.  RR*  /\  x  e. 
RR* )  ->  (
( A  <  x  /\  x  <  B )  ->  A  <  B
) )
873expa 1108 . . . . . . 7  |-  ( ( ( A  e.  RR*  /\  B  e.  RR* )  /\  x  e.  RR* )  ->  ( ( A  < 
x  /\  x  <  B )  ->  A  <  B ) )
98rexlimdva 2387 . . . . . 6  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( E. x  e.  RR*  ( A  <  x  /\  x  <  B )  ->  A  <  B ) )
10 qbtwnxr 9556 . . . . . . . 8  |-  ( ( A  e.  RR*  /\  B  e.  RR*  /\  A  < 
B )  ->  E. x  e.  QQ  ( A  < 
x  /\  x  <  B ) )
11 qre 9415 . . . . . . . . . . 11  |-  ( x  e.  QQ  ->  x  e.  RR )
12 rexr 8279 . . . . . . . . . . 11  |-  ( x  e.  RR  ->  x  e.  RR* )
1311, 12syl 15 . . . . . . . . . 10  |-  ( x  e.  QQ  ->  x  e.  RR* )
1413anim1i 544 . . . . . . . . 9  |-  ( ( x  e.  QQ  /\  ( A  <  x  /\  x  <  B ) )  ->  ( x  e. 
RR*  /\  ( A  <  x  /\  x  < 
B ) ) )
1514reximi2 2369 . . . . . . . 8  |-  ( E. x  e.  QQ  ( A  <  x  /\  x  <  B )  ->  E. x  e.  RR*  ( A  < 
x  /\  x  <  B ) )
1610, 15syl 15 . . . . . . 7  |-  ( ( A  e.  RR*  /\  B  e.  RR*  /\  A  < 
B )  ->  E. x  e.  RR*  ( A  < 
x  /\  x  <  B ) )
17163expia 1110 . . . . . 6  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( A  <  B  ->  E. x  e.  RR*  ( A  < 
x  /\  x  <  B ) ) )
189, 17impbid 181 . . . . 5  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( E. x  e.  RR*  ( A  <  x  /\  x  <  B )  <->  A  <  B ) )
195, 18syl5bb 246 . . . 4  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( -.  { x  e.  RR*  |  ( A  <  x  /\  x  <  B ) }  =  (/)  <->  A  <  B ) )
20 xrltnle 8289 . . . 4  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( A  <  B  <->  -.  B  <_  A ) )
2119, 20bitrd 242 . . 3  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( -.  { x  e.  RR*  |  ( A  <  x  /\  x  <  B ) }  =  (/)  <->  -.  B  <_  A ) )
2221con4bid 282 . 2  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  ( { x  e.  RR*  |  ( A  <  x  /\  x  <  B ) }  =  (/)  <->  B  <_  A ) )
232, 22bitrd 242 1  |-  ( ( A  e.  RR*  /\  B  e.  RR* )  ->  (
( A (,) B
)  =  (/)  <->  B  <_  A ) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    <-> wb 174    /\ wa 356    /\ w3a 894    = wceq 1518    e. wcel 1520    =/= wne 2180   E.wrex 2273   {crab 2275   (/)c0 3070   class class class wbr 3584  (class class class)co 5356   RRcr 8152    <_ cle 8266   RR*cxr 8269    < clt 8270   QQcq 8395   (,)cioo 9682
This theorem is referenced by:  ioon0  9708  iooid  9710  bndth  16600  ioombl  17064  itgsubstlem  17483  oisbmi  22613  oisbmj  22614
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-1cn 8210  ax-icn 8211  ax-addcl 8212  ax-addrcl 8213  ax-mulcl 8214  ax-mulrcl 8215  ax-mulcom 8216  ax-addass 8217  ax-mulass 8218  ax-distr 8219  ax-i2m1 8220  ax-1ne0 8221  ax-1rid 8222  ax-rnegex 8223  ax-rrecex 8224  ax-cnre 8225  ax-pre-lttri 8226  ax-pre-lttrn 8227  ax-pre-ltadd 8228  ax-pre-mulgt0 8229  ax-pre-sup 8230
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-reu 2278  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-pss 2804  df-nul 3071  df-if 3180  df-pw 3241  df-sn 3259  df-pr 3260  df-tp 3261  df-op 3262  df-uni 3423  df-iun 3500  df-br 3585  df-opab 3639  df-mpt 3640  df-tr 3672  df-eprel 3854  df-id 3858  df-po 3863  df-so 3864  df-fr 3901  df-we 3903  df-ord 3944  df-on 3945  df-lim 3946  df-suc 3947  df-om 4222  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-ov 5359  df-oprab 5360  df-mpt2 5361  df-1st 5610  df-2nd 5611  df-iota 5766  df-recs 5839  df-rdg 5874  df-er 6111  df-en 6298  df-dom 6299  df-sdom 6300  df-riota 6464  df-sup 6672  df-pnf 8271  df-mnf 8272  df-xr 8273  df-ltxr 8274  df-le 8275  df-sub 8408  df-neg 8409  df-div 8640  df-n 8883  df-n0 9076  df-z 9128  df-uz 9326  df-q 9411  df-ioo 9686
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