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<b>let </b><font color="Maroon">Y0</font> be    <a href="pre_topc.html#L1">TopStruct</a> , <font color="Maroon">Y1</font> be    <a href="pre_topc.html#L1">TopStruct</a> ;<br/><b>let </b><font color="Maroon">D0</font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">Y0</font>;<br/><b>let </b><font color="Maroon">D1</font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">Y1</font>;<br/>





<b>assume </b><a NAME="E1:5"/><i><font color="Green">E17</font></i>: 
 <a href="pre_topc.html#G1">TopStruct</a>(# the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">Y0</font>,the <a href="pre_topc.html#U1">topology</a> of <font color="Maroon">Y0</font> #) <a href="hidden.html#R1">=</a>  <a href="pre_topc.html#G1">TopStruct</a>(# the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">Y1</font>,the <a href="pre_topc.html#U1">topology</a> of <font color="Maroon">Y1</font> #)
 ;<br/>

<b>assume </b><a NAME="E2:5"/><i><font color="Green">E18</font></i>: 
<font color="Maroon">D0</font> <a href="hidden.html#R1">=</a> <font color="Maroon">D1</font>
 ;<br/>

<b>assume </b><a NAME="E3:5"/><i><font color="Green">E19</font></i>: 
<font color="Maroon">D0</font> is <a href="tsp_2.html#V1" target="_self">maximal_T_0</a>
 ;<br/>

<a NAME="E4:5"/><b>then </b>
<font color="Maroon">D0</font> is <a href="tsp_1.html#V1">T_0</a>
 
<b>by </b><i/>;<br/>
<a NAME="E5:5"/><b>then </b><i><font color="Green">E21</font></i>: 
<font color="Maroon">D1</font> is <a href="tsp_1.html#V1">T_0</a>
 
<b>by </b><i>, , <a class="ref" href="tsp_1.html#T5">TSP_1:5</a></i>;<br/>
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="5_1"><b>now </b></a><div class="add"><b>let </b><font color="Maroon">D</font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">Y1</font>;<br/><b>assume </b><a NAME="E1:5_1"/><i><font color="Green">E22</font></i>: 
<font color="Maroon">D</font> is <a href="tsp_1.html#V1">T_0</a>
 ;<br/><b>assume </b><a NAME="E2:5_1"/><i><font color="Green">E23</font></i>: 
<font color="Maroon">D1</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">D</font>
 ;<br/><b>reconsider </b><font color="Maroon">E</font> = <font color="Maroon">D</font> as   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">Y0</font> <b>by </b><i/>;<br/><a NAME="E4:5_1"/>
( <font color="Maroon">E</font> is <a href="tsp_1.html#V1">T_0</a> &amp; <font color="Maroon">D0</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">E</font> )
 <b>by </b><i>, , , , <a class="ref" href="tsp_1.html#T5">TSP_1:5</a></i>;<br/><b>hence </b><a NAME="E5:5_1"/>
<font color="Maroon">D1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">D</font>
 <b>by </b><i>, , </i>;<br/></div><b>end;</b></div>
<b>hence </b><a NAME="E7:5"/>
<font color="Maroon">D1</font> is <a href="tsp_2.html#V1" target="_self">maximal_T_0</a>
 <b>by </b><i>, </i>;<br/>


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