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<b>let </b><font color="Maroon">T1</font> be  <a href="pre_topc.html#V1">strict</a> <a href="pre_topc.html#NM1">TopSpace</a>, <font color="Maroon">T2</font> be  <a href="pre_topc.html#V1">strict</a> <a href="pre_topc.html#NM1">TopSpace</a>;<br/>

<b>assume </b><b>that </b><br/><a NAME="E1:60_1_2"/><i><font color="Green">E50</font></i>: 
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">X</font>
 <b>and </b><br/><a NAME="E2:60_1_2"/><i><font color="Green">E58</font></i>: 
for <font color="Olive">A</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> holds   <a href="tops_1.html#K1">Int</a> <font color="Olive">A</font> <a href="hidden.html#R1">=</a>  <a href="cqc_lang.html#K2">IFEQ</a> <font color="Olive">A</font>,<font color="Maroon">X</font>,<font color="Olive">A</font>,<span class="p1">(<span class="default"><font color="Olive">A</font> <a href="subset_1.html#K8">/\</a> <font color="Maroon">X0</font></span>)</span>
 <b>and </b><br/><a NAME="E3:60_1_2"/><i><font color="Green">E60</font></i>: 
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T2</font> <a href="hidden.html#R1">=</a> <font color="Maroon">X</font>
 <b>and </b><br/><a NAME="E4:60_1_2"/><i><font color="Green">E62</font></i>: 
for <font color="Olive">A</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> holds   <a href="tops_1.html#K1">Int</a> <font color="Olive">A</font> <a href="hidden.html#R1">=</a>  <a href="cqc_lang.html#K2">IFEQ</a> <font color="Olive">A</font>,<font color="Maroon">X</font>,<font color="Olive">A</font>,<span class="p1">(<span class="default"><font color="Olive">A</font> <a href="subset_1.html#K8">/\</a> <font color="Maroon">X0</font></span>)</span>
 ;<br/>

<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="60_1_2_1"><b>now </b></a><div class="add"><b>let </b><font color="Maroon">A1</font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font>;<br/><b>let </b><font color="Maroon">A2</font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font>;<br/><b>assume </b><a NAME="E1:60_1_2_1"/>
<font color="Maroon">A1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">A2</font>
 ;<br/><b>hence </b> <a href="tops_1.html#K1">Int</a> <font color="Maroon">A1</font> = 
 <a href="cqc_lang.html#K2">IFEQ</a> <font color="Maroon">A2</font>,<font color="Maroon">X</font>,<font color="Maroon">A2</font>,<span class="p1">(<span class="default"><font color="Maroon">A2</font> <a href="subset_1.html#K8">/\</a> <font color="Maroon">X0</font></span>)</span>
<b>by </b><i/>
<br/>.= 
 <a href="tops_1.html#K1">Int</a> <font color="Maroon">A2</font>
<b>by </b><i/>
;<br/><br/></div><b>end;</b></div>
<b>hence </b><a NAME="E6:60_1_2"/>
<font color="Maroon">T1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">T2</font>
 <b>by </b><i>, , </i>;<br/>


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