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<b>let </b><font color="Maroon" title="c1">a</font>, <font color="Maroon" title="c2">b</font>, <font color="Maroon" title="c3">c</font>, <font color="Maroon" title="c4">d</font> be  <a href="xxreal_0.html#V1" title="XXREAL_0:attr.1">ext-real</a>  <a href="ordinal1.html#NM1" title="ORDINAL1:NM.1">number</a> ;<br/>







<a NAME="E1:38"/><i><font color="Green" title="E25">A1</font></i>: 
( <font color="Maroon" title="c2">b</font> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a>  <a href="xxreal_0.html#K4" title="XXREAL_0:func.4">max</a> <font color="Maroon" title="c2">b</font>,<font color="Maroon" title="c4">d</font> &amp; <font color="Maroon" title="c4">d</font> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a>  <a href="xxreal_0.html#K4" title="XXREAL_0:func.4">max</a> <font color="Maroon" title="c2">b</font>,<font color="Maroon" title="c4">d</font> )
 
<b>by </b><i><a class="ref" href="xxreal_0.html#T25" target="_self" title="XXREAL_0:th.25">Th25</a></i>;<br/>
<b>assume </b><a NAME="E2:38"/>
( <font color="Maroon" title="c1">a</font> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a> <font color="Maroon" title="c2">b</font> &amp; <font color="Maroon" title="c3">c</font> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a> <font color="Maroon" title="c4">d</font> )
 ;<br/>

<a NAME="E3:38"/><b>then </b>
( <font color="Maroon" title="c1">a</font> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a>  <a href="xxreal_0.html#K4" title="XXREAL_0:func.4">max</a> <font color="Maroon" title="c2">b</font>,<font color="Maroon" title="c4">d</font> &amp; <font color="Maroon" title="c3">c</font> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a>  <a href="xxreal_0.html#K4" title="XXREAL_0:func.4">max</a> <font color="Maroon" title="c2">b</font>,<font color="Maroon" title="c4">d</font> )
 
<b>by </b><i><a class="txt" href="xxreal_0.html#E1:38"><i><font color="Green" title="E25">A1</font></i></a>, <a class="ref" href="xxreal_0.html#T2" target="_self" title="XXREAL_0:th.2">Th2</a></i>;<br/>
<b>hence </b><a NAME="E4:38"/>
 <a href="xxreal_0.html#K4" title="XXREAL_0:func.4">max</a> <font color="Maroon" title="c1">a</font>,<font color="Maroon" title="c3">c</font> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a>  <a href="xxreal_0.html#K4" title="XXREAL_0:func.4">max</a> <font color="Maroon" title="c2">b</font>,<font color="Maroon" title="c4">d</font>
 <b>by </b><i><a class="ref" href="xxreal_0.html#D9" target="_self" title="XXREAL_0:def.9">Def9</a></i>;<br/>


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