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<div class="add">

<b>let </b><font color="Maroon" title="c1">X</font> be  non <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a>  <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/><b>let </b><font color="Maroon" title="c2">Y</font> be  non <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a> <a href="subset_1.html#NM2" title="SUBSET_1:NM.2">Subset</a> of <a href="numbers.html#K6" title="NUMBERS:func.6">ExtREAL</a> ;<br/><b>let </b><font color="Maroon" title="c3">F</font> be   <a href="funct_2.html#NM1" title="FUNCT_2:NM.1">Function</a> of <font color="Maroon" title="c1">X</font>,<font color="Maroon" title="c2">Y</font>;<br/>





<b>assume </b><a NAME="E1:65"/><i><font color="Green" title="E51">A1</font></i>: 
<font color="Maroon" title="c2">Y</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a>  <a href="supinf_1.html#K3" title="SUPINF_1:func.3">REAL</a> 
 ;<br/>

<b>thus </b><a NAME="E2:65"/>
( <font color="Maroon" title="c3">F</font> is <a href="supinf_2.html#V3" title="SUPINF_2:attr.3">bounded</a> implies (  <a href="supinf_2.html#K11" title="SUPINF_2:func.11">inf</a> <font color="Maroon" title="c3">F</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="supinf_1.html#K3" title="SUPINF_1:func.3">REAL</a>  &amp;  <a href="supinf_2.html#K10" title="SUPINF_2:func.10">sup</a> <font color="Maroon" title="c3">F</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="supinf_1.html#K3" title="SUPINF_1:func.3">REAL</a>  ) )
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="65_1"><b>proof </b></a><div class="add">

<b>assume </b><a NAME="E1:65_1"/>
<font color="Maroon" title="c3">F</font> is <a href="supinf_2.html#V3" title="SUPINF_2:attr.3">bounded</a>
 ;<br/>

<a NAME="E2:65_1"/><b>then </b>
( <font color="Maroon" title="c3">F</font> is <a href="supinf_2.html#V1" title="SUPINF_2:attr.1">bounded_above</a> &amp; <font color="Maroon" title="c3">F</font> is <a href="supinf_2.html#V2" title="SUPINF_2:attr.2">bounded_below</a> )
 
<b>by </b><i><a class="ref" href="supinf_2.html#D13" target="_self" title="SUPINF_2:def.13">Def13</a></i>;<br/>
<b>hence </b><a NAME="E3:65_1"/>
(  <a href="supinf_2.html#K11" title="SUPINF_2:func.11">inf</a> <font color="Maroon" title="c3">F</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="supinf_1.html#K3" title="SUPINF_1:func.3">REAL</a>  &amp;  <a href="supinf_2.html#K10" title="SUPINF_2:func.10">sup</a> <font color="Maroon" title="c3">F</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="supinf_1.html#K3" title="SUPINF_1:func.3">REAL</a>  )
 <b>by </b><i><a class="txt" href="supinf_2.html#E1:65"><i><font color="Green" title="E51">A1</font></i></a>, <a class="ref" href="supinf_2.html#T46" target="_self" title="SUPINF_2:th.46">Th46</a>, <a class="ref" href="supinf_2.html#T47" target="_self" title="SUPINF_2:th.47">Th47</a></i>;<br/>


</div><b>end;</b></div>

<b>assume </b><a NAME="E3:65"/>
(  <a href="supinf_2.html#K11" title="SUPINF_2:func.11">inf</a> <font color="Maroon" title="c3">F</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="supinf_1.html#K3" title="SUPINF_1:func.3">REAL</a>  &amp;  <a href="supinf_2.html#K10" title="SUPINF_2:func.10">sup</a> <font color="Maroon" title="c3">F</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="supinf_1.html#K3" title="SUPINF_1:func.3">REAL</a>  )
 ;<br/>

<a NAME="E4:65"/><b>then </b>
( <font color="Maroon" title="c3">F</font> is <a href="supinf_2.html#V1" title="SUPINF_2:attr.1">bounded_above</a> &amp; <font color="Maroon" title="c3">F</font> is <a href="supinf_2.html#V2" title="SUPINF_2:attr.2">bounded_below</a> )
 
<b>by </b><i><a class="txt" href="supinf_2.html#E1:65"><i><font color="Green" title="E51">A1</font></i></a>, <a class="ref" href="supinf_2.html#T46" target="_self" title="SUPINF_2:th.46">Th46</a>, <a class="ref" href="supinf_2.html#T47" target="_self" title="SUPINF_2:th.47">Th47</a></i>;<br/>
<b>hence </b><a NAME="E5:65"/>
<font color="Maroon" title="c3">F</font> is <a href="supinf_2.html#V3" title="SUPINF_2:attr.3">bounded</a>
 <b>by </b><i><a class="ref" href="supinf_2.html#D13" target="_self" title="SUPINF_2:def.13">Def13</a></i>;<br/>


</div>
