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<b>let </b><font color="Maroon" title="c12">F</font> be   <a href="vectsp_1.html#NM3" title="VECTSP_1:NM.3">Field</a>;<br/><b>let </b><font color="Maroon" title="c13">x</font>, <font color="Maroon" title="c14">y</font> be    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of <font color="Maroon">H<sub>1</sub></font>(<font color="Maroon" title="c12">F</font>) <a href="subset_1.html#K6" title="SUBSET_1:func.6">\</a> <span class="p1"><a href="domain_1.html#K6" title="DOMAIN_1:func.6">{</a><span class="default"><span class="p2">(<span class="default"><a href="struct_0.html#K4" title="STRUCT_0:func.4">0.</a> <font color="Maroon" title="c12">F</font></span>)</span></span><a href="domain_1.html#K6" title="DOMAIN_1:func.6">}</a></span>;<br/>



<b>assume </b><a NAME="E1:41"/><i><font color="Green" title="E37">A1</font></i>: 
<font color="Maroon" title="c13">x</font> <a href="group_1.html#K9" title="GROUP_1:func.9">*</a> <font color="Maroon" title="c14">y</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="struct_0.html#K5" title="STRUCT_0:func.5">1.</a> <font color="Maroon" title="c12">F</font>
 ;<br/>

<b>reconsider </b><font color="Maroon" title="c15">rx</font> = <span class="p1">(<span class="default"><a href="realset2.html#K5" title="REALSET2:func.5">revf</a> <font color="Maroon" title="c12">F</font></span>)</span> <a href="funct_2.html#K3" title="FUNCT_2:func.3">.</a> <font color="Maroon" title="c13">x</font> as   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c12">F</font> <b>by </b><i><a class="ref" href="xboole_0.html#D4" title="XBOOLE_0:def.4">XBOOLE_0:def 4</a></i>;<br/>
<font color="Maroon" title="c14">y</font> = 
<font color="Maroon" title="c14">y</font> <a href="group_1.html#K9" title="GROUP_1:func.9">*</a> <span class="p1">(<span class="default"><a href="struct_0.html#K5" title="STRUCT_0:func.5">1.</a> <font color="Maroon" title="c12">F</font></span>)</span>
<b>by </b><i><a class="ref" href="realset2.html#T10" target="_self" title="REALSET2:th.10">Th10</a></i>
<br/>.= 
<span class="p1">(<span class="default"><a href="realset2.html#K4" title="REALSET2:func.4">omf</a> <font color="Maroon" title="c12">F</font></span>)</span> <a href="binop_1.html#K4" title="BINOP_1:func.4">.</a> <font color="Maroon" title="c14">y</font>,<span class="p1">(<span class="default"><a href="struct_0.html#K5" title="STRUCT_0:func.5">1.</a> <font color="Maroon" title="c12">F</font></span>)</span>

<br/>.= 
<font color="Maroon" title="c14">y</font> <a href="group_1.html#K9" title="GROUP_1:func.9">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c13">x</font> <a href="group_1.html#K9" title="GROUP_1:func.9">*</a> <font color="Maroon" title="c15">rx</font></span>)</span>
<b>by </b><i><a class="ref" href="realset2.html#D18" target="_self" title="REALSET2:def.18">Def18</a></i>
<br/>.= 
<span class="p1">(<span class="default"><a href="struct_0.html#K5" title="STRUCT_0:func.5">1.</a> <font color="Maroon" title="c12">F</font></span>)</span> <a href="group_1.html#K9" title="GROUP_1:func.9">*</a> <font color="Maroon" title="c15">rx</font>
<b>by </b><i><a class="txt" href="realset2.html#E1:41"><i><font color="Green" title="E37">A1</font></i></a>, <a class="ref" href="realset2.html#T8" target="_self" title="REALSET2:th.8">Th8</a></i>
<br/>.= 
<span class="p1">(<span class="default"><a href="realset2.html#K5" title="REALSET2:func.5">revf</a> <font color="Maroon" title="c12">F</font></span>)</span> <a href="funct_2.html#K3" title="FUNCT_2:func.3">.</a> <font color="Maroon" title="c13">x</font>
<b>by </b><i><a class="ref" href="realset2.html#T10" target="_self" title="REALSET2:th.10">Th10</a></i>
;<br/>
<b>hence </b><a NAME="E4:41"/>
<font color="Maroon" title="c14">y</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><a href="realset2.html#K5" title="REALSET2:func.5">revf</a> <font color="Maroon" title="c12">F</font></span>)</span> <a href="funct_2.html#K3" title="FUNCT_2:func.3">.</a> <font color="Maroon" title="c13">x</font>
 ;<br/>


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