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Theorem mnflt 9599
Description: Minus infinity is less than any (finite) real. (Contributed by NM, 14-Oct-2005.)
Assertion
Ref Expression
mnflt  |-  ( A  e.  RR  -> -oo  <  A )

Proof of Theorem mnflt
StepHypRef Expression
1 eqid 2140 . . . 4  |- -oo  = -oo
2 olc 701 . . . 4  |-  ( ( -oo  = -oo  /\  A  e.  RR )  ->  ( ( -oo  e.  RR  /\  A  = +oo )  \/  ( -oo  = -oo  /\  A  e.  RR ) ) )
31, 2mpan 421 . . 3  |-  ( A  e.  RR  ->  (
( -oo  e.  RR  /\  A  = +oo )  \/  ( -oo  = -oo  /\  A  e.  RR ) ) )
43olcd 724 . 2  |-  ( A  e.  RR  ->  (
( ( ( -oo  e.  RR  /\  A  e.  RR )  /\ -oo  <RR  A )  \/  ( -oo  = -oo  /\  A  = +oo ) )  \/  ( ( -oo  e.  RR  /\  A  = +oo )  \/  ( -oo  = -oo  /\  A  e.  RR ) ) ) )
5 mnfxr 7846 . . 3  |- -oo  e.  RR*
6 rexr 7835 . . 3  |-  ( A  e.  RR  ->  A  e.  RR* )
7 ltxr 9592 . . 3  |-  ( ( -oo  e.  RR*  /\  A  e.  RR* )  ->  ( -oo  <  A  <->  ( (
( ( -oo  e.  RR  /\  A  e.  RR )  /\ -oo  <RR  A )  \/  ( -oo  = -oo  /\  A  = +oo ) )  \/  (
( -oo  e.  RR  /\  A  = +oo )  \/  ( -oo  = -oo  /\  A  e.  RR ) ) ) ) )
85, 6, 7sylancr 411 . 2  |-  ( A  e.  RR  ->  ( -oo  <  A  <->  ( (
( ( -oo  e.  RR  /\  A  e.  RR )  /\ -oo  <RR  A )  \/  ( -oo  = -oo  /\  A  = +oo ) )  \/  (
( -oo  e.  RR  /\  A  = +oo )  \/  ( -oo  = -oo  /\  A  e.  RR ) ) ) ) )
94, 8mpbird 166 1  |-  ( A  e.  RR  -> -oo  <  A )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 103    <-> wb 104    \/ wo 698    = wceq 1332    e. wcel 1481   class class class wbr 3937   RRcr 7643    <RR cltrr 7648   +oocpnf 7821   -oocmnf 7822   RR*cxr 7823    < clt 7824
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 699  ax-5 1424  ax-7 1425  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-8 1483  ax-10 1484  ax-11 1485  ax-i12 1486  ax-bndl 1487  ax-4 1488  ax-13 1492  ax-14 1493  ax-17 1507  ax-i9 1511  ax-ial 1515  ax-i5r 1516  ax-ext 2122  ax-sep 4054  ax-pow 4106  ax-pr 4139  ax-un 4363  ax-cnex 7735
This theorem depends on definitions:  df-bi 116  df-3an 965  df-tru 1335  df-nf 1438  df-sb 1737  df-eu 2003  df-mo 2004  df-clab 2127  df-cleq 2133  df-clel 2136  df-nfc 2271  df-ral 2422  df-rex 2423  df-v 2691  df-un 3080  df-in 3082  df-ss 3089  df-pw 3517  df-sn 3538  df-pr 3539  df-op 3541  df-uni 3745  df-br 3938  df-opab 3998  df-xp 4553  df-pnf 7826  df-mnf 7827  df-xr 7828  df-ltxr 7829
This theorem is referenced by:  mnflt0  9600  mnfltxr  9602  xrlttr  9611  xrltso  9612  xrlttri3  9613  ngtmnft  9630  nmnfgt  9631  xrrebnd  9632  xrre3  9635  xltnegi  9648  xltadd1  9689  xposdif  9695  elico2  9750  elicc2  9751  ioomax  9761  elioomnf  9781  qbtwnxr  10066  tgioo  12754
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