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<b>let </b><font color="Maroon">V</font> be   <a href="bhsp_1.html#NM1">RealUnitarySpace</a>;<br/><b>let </b><font color="Maroon">M</font> be   <a href="struct_0.html#NM2">Subset</a> of <span class="p1">(<span class="default"><a href="rusub_5.html#K5" target="_self">TopUnitSpace</a> <font color="Maroon">V</font></span>)</span>;<br/><b>let </b><font color="Maroon">r</font> be   <a href="real_1.html#NM1">Real</a>;<br/><b>let </b><font color="Maroon">v</font> be   <a href="pre_topc.html#NM2">Point</a> of <font color="Maroon">V</font>;<br/>







<b>assume </b><a NAME="E1:57"/>
<font color="Maroon">M</font> <a href="hidden.html#R1">=</a>  <a href="bhsp_2.html#K4">Ball</a> <font color="Maroon">v</font>,<font color="Maroon">r</font>
 ;<br/>

<a NAME="E2:57"/><b>then </b><i><font color="Green">E23</font></i>: 
<font color="Maroon">M</font> <a href="hidden.html#R2">in</a>  <a href="rusub_5.html#K4" target="_self">Family_open_set</a> <font color="Maroon">V</font>
 
<b>by </b><i/>;<br/>
<b>thus </b><a NAME="E3:57"/>
<font color="Maroon">M</font> is <a href="pre_topc.html#V3">open</a>
 <b>by </b><i>, <a class="ref" href="pre_topc.html#D5">PRE_TOPC:def 5</a></i>;<br/>


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