<?xml version="1.0"?>
<div class="add">

<b>let </b><font color="Maroon">T1</font> be  non <a href="struct_0.html#V3">empty</a> <a href="pre_topc.html#NM1">TopSpace</a>, <font color="Maroon">T2</font> be  non <a href="struct_0.html#V3">empty</a> <a href="pre_topc.html#NM1">TopSpace</a>;<br/>

<b>set </b><font color="Maroon">T</font> = <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span>;<br/>
<b>let </b><font color="Maroon">B1</font> be    <a href="cantor_1.html#M2">prebasis</a> of <font color="Maroon">T1</font>;<br/><b>let </b><font color="Maroon">B2</font> be    <a href="cantor_1.html#M2">prebasis</a> of <font color="Maroon">T2</font>;<br/>



<b>set </b><font color="Maroon">C2</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default">the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T1</font>,<font color="Olive">b</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">b</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B2</font> </span>}</span> ;<br/>
<b>set </b><font color="Maroon">C1</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default"><font color="Olive">a</font>,the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T2</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">a</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B1</font> </span>}</span> ;<br/>
<b>reconsider </b><font color="Maroon">D1</font> =  <a href="cantor_1.html#K2">FinMeetCl</a> <font color="Maroon">B1</font> as    <a href="cantor_1.html#M1">Basis</a> of <font color="Maroon">T1</font> <b>by </b><i/>;<br/>
<b>reconsider </b><font color="Maroon">D2</font> =  <a href="cantor_1.html#K2">FinMeetCl</a> <font color="Maroon">B2</font> as    <a href="cantor_1.html#M1">Basis</a> of <font color="Maroon">T2</font> <b>by </b><i/>;<br/>
<b>reconsider </b><font color="Maroon">D</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">a</font>,<font color="Olive">b</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">a</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font>, <font color="Olive">b</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : ( <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">D1</font> &amp; <font color="Olive">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">D2</font> ) </span>}</span>  as    <a href="cantor_1.html#M1">Basis</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span> <b>by </b><i/>;<br/>
<a NAME="E4:59"/>
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T1</font> <a href="tarski.html#R1">c=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T1</font>
 
;<br/>
<b>then reconsider </b><font color="Maroon">cT1</font> = the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T1</font> as   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> ;<br/>
<a NAME="E6:59"/>
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T2</font> <a href="tarski.html#R1">c=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T2</font>
 
;<br/>
<b>then reconsider </b><font color="Maroon">cT2</font> = the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T2</font> as   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> ;<br/>
<a NAME="E8:59"/><i><font color="Green">E32</font></i>: 
( <font color="Maroon">cT1</font> <a href="hidden.html#R2">in</a> the <a href="pre_topc.html#U1">topology</a> of <font color="Maroon">T1</font> &amp; <font color="Maroon">cT2</font> <a href="hidden.html#R2">in</a> the <a href="pre_topc.html#U1">topology</a> of <font color="Maroon">T2</font> )
 
<b>by </b><i><a class="ref" href="pre_topc.html#D1">PRE_TOPC:def 1</a></i>;<br/>
<a NAME="E9:59"/><i><font color="Green">E33</font></i>: 
( <font color="Maroon">B1</font> <a href="tarski.html#R1">c=</a> the <a href="pre_topc.html#U1">topology</a> of <font color="Maroon">T1</font> &amp; <font color="Maroon">B2</font> <a href="tarski.html#R1">c=</a> the <a href="pre_topc.html#U1">topology</a> of <font color="Maroon">T2</font> )
 
<b>by </b><i><a class="ref" href="cantor_1.html#D5">CANTOR_1:def 5</a></i>;<br/>
<a NAME="E10:59"/>
<span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default"><font color="Olive">a</font>,the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T2</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">a</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B1</font> </span>}</span>  <a href="tarski.html#R1">c=</a>  <a href="zfmisc_1.html#K1">bool</a> the <a href="struct_0.html#U1">carrier</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="59_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a><br/>

<b>assume </b><a NAME="E1:59_1"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default"><font color="Olive">a</font>,the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T2</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">a</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B1</font> </span>}</span> 
 ;<br/>

<a NAME="E2:59_1"/><b>then </b>
 ex <font color="Olive">a</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> st <br/>( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">a</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B1</font> )
 
;<br/>
<b>hence </b><a NAME="E3:59_1"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a>  <a href="zfmisc_1.html#K1">bool</a> the <a href="struct_0.html#U1">carrier</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span>
 ;<br/>


</div><b>end;</b></div>
<b>then reconsider </b><font color="Maroon">C1</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default"><font color="Olive">a</font>,the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T2</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">a</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B1</font> </span>}</span>  as   <a href="struct_0.html#NM3">Subset-Family</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span> ;<br/>
<b>reconsider </b><font color="Maroon">C1</font> = <font color="Maroon">C1</font> as   <a href="struct_0.html#NM3">Subset-Family</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span> ;<br/>
<a NAME="E13:59"/>
<span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default">the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T1</font>,<font color="Olive">b</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">b</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B2</font> </span>}</span>  <a href="tarski.html#R1">c=</a>  <a href="zfmisc_1.html#K1">bool</a> the <a href="struct_0.html#U1">carrier</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="59_2"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a><br/>

<b>assume </b><a NAME="E1:59_2"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default">the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T1</font>,<font color="Olive">b</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">b</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B2</font> </span>}</span> 
 ;<br/>

<a NAME="E2:59_2"/><b>then </b>
 ex <font color="Olive">a</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> st <br/>( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">a</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B2</font> )
 
;<br/>
<b>hence </b><a NAME="E3:59_2"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a>  <a href="zfmisc_1.html#K1">bool</a> the <a href="struct_0.html#U1">carrier</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span>
 ;<br/>


</div><b>end;</b></div>
<b>then reconsider </b><font color="Maroon">C2</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default">the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T1</font>,<font color="Olive">b</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">b</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B2</font> </span>}</span>  as   <a href="struct_0.html#NM3">Subset-Family</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span> ;<br/>
<b>reconsider </b><font color="Maroon">C2</font> = <font color="Maroon">C2</font> as   <a href="struct_0.html#NM3">Subset-Family</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span> ;<br/>
<b>reconsider </b><font color="Maroon">C</font> = <font color="Maroon">C2</font> <a href="subset_1.html#K4">\/</a> <font color="Maroon">C1</font> as   <a href="struct_0.html#NM3">Subset-Family</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span> ;<br/>
<a NAME="E17:59"/>
<font color="Maroon">C</font> is    <a href="cantor_1.html#M2">prebasis</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="59_3"><b>proof </b></a><div class="add">

<div><b>hereby </b> <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a>,<a class="ref" href="cantor_1.html#D5">CANTOR_1:def 5</a>
<div class="add"><b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>assume </b><a NAME="E1:59_3_1"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">C</font>
 ;<br/><a NAME="E2:59_3_1"/><b>then </b>
( <font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">C1</font> or <font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">C2</font> )
 <b>by </b><i><a class="ref" href="xboole_0.html#D2">XBOOLE_0:def 2</a></i>;<br/><a NAME="E3:59_3_1"/><b>then </b>
(  ex <font color="Olive">a</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> st <br/>( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">a</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B1</font> ) or  ex <font color="Olive">a</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> st <br/>( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">a</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B2</font> ) )
 ;<br/><b>then consider </b><font color="Maroon">a</font> being   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font>, <font color="Maroon">b</font> being   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font><b> such that </b><br/><a NAME="E5:59_3_1"/><i><font color="Green">E35</font></i>: 
( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Maroon">a</font> <a href="hidden.html#R2">in</a> the <a href="pre_topc.html#U1">topology</a> of <font color="Maroon">T1</font> &amp; <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> the <a href="pre_topc.html#U1">topology</a> of <font color="Maroon">T2</font> )
 <b>by </b><i>, <a class="txt" href="yellow_9.html#E8:59"><i><font color="Green">E32</font></i></a></i>;<br/><a NAME="E6:59_3_1"/>
( <font color="Maroon">a</font> is <a href="pre_topc.html#V3">open</a> &amp; <font color="Maroon">b</font> is <a href="pre_topc.html#V3">open</a> )
 <b>by </b><i><a class="txt" href="yellow_9.html#E9:59"><i><font color="Green">E33</font></i></a>, <a class="ref" href="pre_topc.html#D5">PRE_TOPC:def 5</a></i>;<br/><a NAME="E7:59_3_1"/><b>then </b>
<span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="borsuk_1.html#K6">:]</a></span> is <a href="pre_topc.html#V3">open</a>
 <b>by </b><i><a class="ref" href="borsuk_1.html#T46">BORSUK_1:46</a></i>;<br/><b>hence </b><a NAME="E8:59_3_1"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> the <a href="pre_topc.html#U1">topology</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span>
 <b>by </b><i><a class="txt" href="yellow_9.html#E9:59"><i><font color="Green">E33</font></i></a>, <a class="ref" href="pre_topc.html#D5">PRE_TOPC:def 5</a></i>;<br/></div>
<b>end;</b></div>

<b>take </b>
<font color="Maroon">D</font>
;<br/>

<b>let </b><font color="Maroon">d</font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a><br/>

<b>assume </b><a NAME="E2:59_3"/>
<font color="Maroon">d</font> <a href="hidden.html#R2">in</a> <font color="Maroon">D</font>
 ;<br/>

<b>then consider </b><font color="Maroon">a</font> being   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font>, <font color="Maroon">b</font> being   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font><b> such that </b><br/><a NAME="E4:59_3"/><i><font color="Green">E37</font></i>: 
( <font color="Maroon">d</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Maroon">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">D1</font> &amp; <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">D2</font> )
 ;<br/>
<b>consider </b><font color="Maroon">aY</font> being   <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T1</font><b> such that </b><br/><a NAME="E6:59_3"/><i><font color="Green">E38</font></i>: 
<font color="Maroon">aY</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">B1</font>
 <b>and </b><br/><a NAME="E7:59_3"/><i><font color="Green">E52</font></i>: 
<font color="Maroon">aY</font> is <a href="finset_1.html#V1">finite</a>
 <b>and </b><br/><a NAME="E8:59_3"/><i><font color="Green">E53</font></i>: 
<font color="Maroon">a</font> <a href="hidden.html#R1">=</a>  <a href="setfam_1.html#K8">Intersect</a> <font color="Maroon">aY</font>
 <b>by </b><i><a class="txt" href="yellow_9.html#E9:59"><i><font color="Green">E33</font></i></a>, <a class="ref" href="cantor_1.html#D4">CANTOR_1:def 4</a></i>;<br/>
<b>consider </b><font color="Maroon">bY</font> being   <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T2</font><b> such that </b><br/><a NAME="E10:59_3"/><i><font color="Green">E54</font></i>: 
<font color="Maroon">bY</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">B2</font>
 <b>and </b><br/><a NAME="E11:59_3"/><i><font color="Green">E55</font></i>: 
<font color="Maroon">bY</font> is <a href="finset_1.html#V1">finite</a>
 <b>and </b><br/><a NAME="E12:59_3"/><i><font color="Green">E56</font></i>: 
<font color="Maroon">b</font> <a href="hidden.html#R1">=</a>  <a href="setfam_1.html#K8">Intersect</a> <font color="Maroon">bY</font>
 <b>by </b><i><a class="txt" href="yellow_9.html#E9:59"><i><font color="Green">E33</font></i></a>, <a class="ref" href="cantor_1.html#D4">CANTOR_1:def 4</a></i>;<br/>
<b>deffunc </b><font color="Maroon">H<sub>1</sub></font>(  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font>) <b>-&gt; </b>   <a href="subset_1.html#M1">Element</a> of  <a href="zfmisc_1.html#K1">bool</a> the <a href="struct_0.html#U1">carrier</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span> = <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">a<sub>1</sub></font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span>;<br/>
<a NAME="E13:59_3"/><i><font color="Green">E88</font></i>: 
<span class="p1">{<span class="default"> <font color="Maroon">H<sub>1</sub></font>(<font color="Olive">s</font>) where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span>  is <a href="finset_1.html#V1">finite</a>
 
<b>from </b><i><a class="ref" href="fraenkel.html#S21">FRAENKEL:sch 21</a>();<br/></i>
<b>deffunc </b><font color="Maroon">H<sub>2</sub></font>(  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font>) <b>-&gt; </b>   <a href="subset_1.html#M1">Element</a> of  <a href="zfmisc_1.html#K1">bool</a> the <a href="struct_0.html#U1">carrier</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span> = <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Maroon">a<sub>1</sub></font></span><a href="borsuk_1.html#K6">:]</a></span>;<br/>
<a NAME="E14:59_3"/><i><font color="Green">E89</font></i>: 
<span class="p1">{<span class="default"> <font color="Maroon">H<sub>2</sub></font>(<font color="Olive">s</font>) where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span>  is <a href="finset_1.html#V1">finite</a>
 
<b>from </b><i><a class="ref" href="fraenkel.html#S21">FRAENKEL:sch 21</a>(<a class="txt" href="yellow_9.html#E6:59_3"><i><font color="Green">E38</font></i></a>);<br/></i>
<b>set </b><font color="Maroon">Y1</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span> ;<br/>
<b>set </b><font color="Maroon">Y2</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span> ;<br/>
<a NAME="E15:59_3"/><i><font color="Green">E91</font></i>: 
<span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span>  <a href="tarski.html#R1">c=</a> <font color="Maroon">C</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="59_3_2"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a><br/>

<b>assume </b><a NAME="E1:59_3_2"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span> 
 ;<br/>

<b>then consider </b><font color="Maroon">s</font> being   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font><b> such that </b><br/><a NAME="E3:59_3_2"/><i><font color="Green">E92</font></i>: 
( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Maroon">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> )
 ;<br/>
<a NAME="E4:59_3_2"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">C1</font>
 
<b>by </b><i>, </i>;<br/>
<b>hence </b><a NAME="E5:59_3_2"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">C</font>
 <b>by </b><i><a class="ref" href="xboole_0.html#D2">XBOOLE_0:def 2</a></i>;<br/>


</div><b>end;</b></div>
<a NAME="E16:59_3"/><i><font color="Green">E93</font></i>: 
<span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span>  <a href="tarski.html#R1">c=</a> <font color="Maroon">C</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="59_3_3"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a><br/>

<b>assume </b><a NAME="E1:59_3_3"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span> 
 ;<br/>

<b>then consider </b><font color="Maroon">s</font> being   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font><b> such that </b><br/><a NAME="E3:59_3_3"/><i><font color="Green">E94</font></i>: 
( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Maroon">s</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Maroon">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> )
 ;<br/>
<a NAME="E4:59_3_3"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">C2</font>
 
<b>by </b><i><a class="txt" href="yellow_9.html#E4:59_3"><i><font color="Green">E37</font></i></a>, </i>;<br/>
<b>hence </b><a NAME="E5:59_3_3"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">C</font>
 <b>by </b><i><a class="ref" href="xboole_0.html#D2">XBOOLE_0:def 2</a></i>;<br/>


</div><b>end;</b></div>
<b>set </b><font color="Maroon">Y</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span>  <a href="xboole_0.html#K2">\/</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span> ;<br/>
<a NAME="E17:59_3"/><i><font color="Green">E95</font></i>: 
<span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span>  <a href="xboole_0.html#K2">\/</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span>  <a href="tarski.html#R1">c=</a> <font color="Maroon">C</font>
 
<b>by </b><i>, , <a class="ref" href="xboole_1.html#T8">XBOOLE_1:8</a></i>;<br/>
<a NAME="E18:59_3"/><b>then </b>
<span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span>  <a href="xboole_0.html#K2">\/</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span>  is   <a href="struct_0.html#NM3">Subset-Family</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span>
 
<b>by </b><i><a class="ref" href="xboole_1.html#T1">XBOOLE_1:1</a></i>;<br/>
<b>then reconsider </b><font color="Maroon">Y</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span>  <a href="xboole_0.html#K2">\/</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span>  as   <a href="struct_0.html#NM3">Subset-Family</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span> ;<br/>
<a NAME="E20:59_3"/><i><font color="Green">E96</font></i>: 
<font color="Maroon">Y</font> is <a href="finset_1.html#V1">finite</a>
 
<b>by </b><i>, , <a class="ref" href="finset_1.html#T14">FINSET_1:14</a></i>;<br/>
<a NAME="E21:59_3"/>
 <a href="setfam_1.html#K8">Intersect</a> <font color="Maroon">Y</font> <a href="hidden.html#R1">=</a> <font color="Maroon">d</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="59_3_4"><b>proof </b></a><div class="add">

<div><b>hereby </b> <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a>,<a class="ref" href="xboole_0.html#D10">XBOOLE_0:def 10</a>
<div class="add"><b>let </b><font color="Maroon">p</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>assume </b><a NAME="E1:59_3_4_1"/><i><font color="Green">E98</font></i>: 
<font color="Maroon">p</font> <a href="hidden.html#R2">in</a>  <a href="setfam_1.html#K8">Intersect</a> <font color="Maroon">Y</font>
 ;<br/><b>then consider </b><font color="Maroon">p1</font> being   <a href="pre_topc.html#NM2">Point</a> of <font color="Maroon">T1</font>, <font color="Maroon">p2</font> being   <a href="pre_topc.html#NM2">Point</a> of <font color="Maroon">T2</font><b> such that </b><br/><a NAME="E3:59_3_4_1"/><i><font color="Green">E99</font></i>: 
<font color="Maroon">p</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K7">[</a><span class="default"><font color="Maroon">p1</font>,<font color="Maroon">p2</font></span><a href="borsuk_1.html#K7">]</a></span>
 <b>by </b><i><a class="ref" href="borsuk_1.html#T50">BORSUK_1:50</a></i>;<br/><div><a class="txt" onclick="hs2(this)" href="javascript:()" title="59_3_4_1_1"><b>now </b></a><div class="add"><b>let </b><font color="Maroon">z</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>assume </b><a NAME="E1:59_3_4_1_1"/><i><font color="Green">E100</font></i>: 
<font color="Maroon">z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font>
 ;<br/><b>then reconsider </b><font color="Maroon">z'</font> = <font color="Maroon">z</font> as   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> ;<br/><a NAME="E3:59_3_4_1_1"/>
<span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">z'</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span> 
 <b>by </b><i/>;<br/><a NAME="E4:59_3_4_1_1"/><b>then </b>
<span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">z'</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">Y</font>
 <b>by </b><i><a class="ref" href="xboole_0.html#D2">XBOOLE_0:def 2</a></i>;<br/><a NAME="E5:59_3_4_1_1"/><b>then </b>
<font color="Maroon">p</font> <a href="hidden.html#R2">in</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">z'</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span>
 <b>by </b><i><a class="ref" href="yellow_9.html#T2" target="_self">Th2</a>, <a class="ref" href="setfam_1.html#T58">SETFAM_1:58</a></i>;<br/><b>hence </b><a NAME="E6:59_3_4_1_1"/>
<font color="Maroon">p1</font> <a href="hidden.html#R2">in</a> <font color="Maroon">z</font>
 <b>by </b><i>, <a class="ref" href="zfmisc_1.html#T106">ZFMISC_1:106</a></i>;<br/></div><b>end;</b></div><a NAME="E5:59_3_4_1"/><b>then </b><i><font color="Green">E101</font></i>: 
<font color="Maroon">p1</font> <a href="hidden.html#R2">in</a> <font color="Maroon">a</font>
 <b>by </b><i>, <a class="ref" href="setfam_1.html#T58">SETFAM_1:58</a></i>;<br/><div><a class="txt" onclick="hs2(this)" href="javascript:()" title="59_3_4_1_2"><b>now </b></a><div class="add"><b>let </b><font color="Maroon">z</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>assume </b><a NAME="E1:59_3_4_1_2"/><i><font color="Green">E146</font></i>: 
<font color="Maroon">z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font>
 ;<br/><b>then reconsider </b><font color="Maroon">z'</font> = <font color="Maroon">z</font> as   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> ;<br/><a NAME="E3:59_3_4_1_2"/>
<span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Maroon">z'</font></span><a href="borsuk_1.html#K6">:]</a></span> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span> 
 <b>by </b><i><a class="ref" href="yellow_9.html#T3" target="_self">Th3</a></i>;<br/><a NAME="E4:59_3_4_1_2"/><b>then </b>
<span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Maroon">z'</font></span><a href="borsuk_1.html#K6">:]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">Y</font>
 <b>by </b><i><a class="ref" href="xboole_0.html#D2">XBOOLE_0:def 2</a></i>;<br/><a NAME="E5:59_3_4_1_2"/><b>then </b>
<font color="Maroon">p</font> <a href="hidden.html#R2">in</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Maroon">z'</font></span><a href="borsuk_1.html#K6">:]</a></span>
 <b>by </b><i><a class="ref" href="yellow_9.html#T2" target="_self">Th2</a>, <a class="ref" href="setfam_1.html#T58">SETFAM_1:58</a></i>;<br/><b>hence </b><a NAME="E6:59_3_4_1_2"/>
<font color="Maroon">p2</font> <a href="hidden.html#R2">in</a> <font color="Maroon">z</font>
 <b>by </b><i>, <a class="ref" href="zfmisc_1.html#T106">ZFMISC_1:106</a></i>;<br/></div><b>end;</b></div><a NAME="E7:59_3_4_1"/><b>then </b>
<font color="Maroon">p2</font> <a href="hidden.html#R2">in</a> <font color="Maroon">b</font>
 <b>by </b><i>, <a class="ref" href="setfam_1.html#T58">SETFAM_1:58</a></i>;<br/><b>hence </b><a NAME="E8:59_3_4_1"/>
<font color="Maroon">p</font> <a href="hidden.html#R2">in</a> <font color="Maroon">d</font>
 <b>by </b><i><a class="txt" href="yellow_9.html#E9:59"><i><font color="Green">E33</font></i></a>, , , <a class="ref" href="zfmisc_1.html#T106">ZFMISC_1:106</a></i>;<br/></div>
<b>end;</b></div>

<b>let </b><font color="Maroon">p</font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a><br/>

<b>assume </b><a NAME="E2:59_3_4"/>
<font color="Maroon">p</font> <a href="hidden.html#R2">in</a> <font color="Maroon">d</font>
 ;<br/>

<b>then consider </b><font color="Maroon">p1</font> being    <a href="hidden.html#M1">set</a> , <font color="Maroon">p2</font> being    <a href="hidden.html#M1">set</a> <b> such that </b><br/><a NAME="E4:59_3_4"/><i><font color="Green">E147</font></i>: 
( <font color="Maroon">p1</font> <a href="hidden.html#R2">in</a> <font color="Maroon">a</font> &amp; <font color="Maroon">p2</font> <a href="hidden.html#R2">in</a> <font color="Maroon">b</font> &amp; <span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">p1</font>,<font color="Maroon">p2</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">p</font> )
 <b>by </b><i><a class="txt" href="yellow_9.html#E9:59"><i><font color="Green">E33</font></i></a>, <a class="ref" href="zfmisc_1.html#D2">ZFMISC_1:def 2</a></i>;<br/>
<b>reconsider </b><font color="Maroon">p1</font> = <font color="Maroon">p1</font> as   <a href="pre_topc.html#NM2">Point</a> of <font color="Maroon">T1</font> <b>by </b><i><a class="ref" href="yellow_9.html#T2" target="_self">Th2</a></i>;<br/>
<b>reconsider </b><font color="Maroon">p2</font> = <font color="Maroon">p2</font> as   <a href="pre_topc.html#NM2">Point</a> of <font color="Maroon">T2</font> <b>by </b><i><a class="ref" href="yellow_9.html#T2" target="_self">Th2</a></i>;<br/>
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="59_3_4_2"><b>now </b></a><div class="add"><b>let </b><font color="Maroon">z</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>assume </b><a NAME="E1:59_3_4_2"/><i><font color="Green">E148</font></i>: 
<font color="Maroon">z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">Y</font>
 ;<br/><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="59_3_4_2_1"><b>per </b></a><a class="txt" onclick="hs(this)" href="javascript:()"><b>cases </b></a><span class="hide"><a NAME="E1:59_3_4_2_1"/>
( <font color="Maroon">z</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span>  or <font color="Maroon">z</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span>  )
 </span><b>by </b><i>, <a class="ref" href="xboole_0.html#D2">XBOOLE_0:def 2</a></i>;<br/><div class="add"><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="59_3_4_2_1_1"><b>suppose </b></a><a NAME="E1:59_3_4_2_1_1"/>
<font color="Maroon">z</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Olive">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> </span>}</span> 
 ;<br/><div class="add"><b>then consider </b><font color="Maroon">s</font> being   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font><b> such that </b><br/><a NAME="E3:59_3_4_2_1_1"/><i><font color="Green">E149</font></i>: 
( <font color="Maroon">z</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">s</font>,<font color="Maroon">cT2</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Maroon">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">aY</font> )
 ;<br/><a NAME="E4:59_3_4_2_1_1"/>
<font color="Maroon">p1</font> <a href="hidden.html#R2">in</a> <font color="Maroon">s</font>
 <b>by </b><i>, <a class="ref" href="yellow_9.html#T2" target="_self">Th2</a>, , <a class="ref" href="setfam_1.html#T58">SETFAM_1:58</a></i>;<br/><b>hence </b><a NAME="E5:59_3_4_2_1_1"/>
<span class="p1"><a href="borsuk_1.html#K7">[</a><span class="default"><font color="Maroon">p1</font>,<font color="Maroon">p2</font></span><a href="borsuk_1.html#K7">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">z</font>
 <b>by </b><i>, <a class="ref" href="zfmisc_1.html#T106">ZFMISC_1:106</a></i>;<br/></div><b>end;</b></div><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="59_3_4_2_1_2"><b>suppose </b></a><a NAME="E1:59_3_4_2_1_2"/>
<font color="Maroon">z</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Olive">s</font></span><a href="borsuk_1.html#K6">:]</a></span> where <font color="Olive">s</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> </span>}</span> 
 ;<br/><div class="add"><b>then consider </b><font color="Maroon">s</font> being   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font><b> such that </b><br/><a NAME="E3:59_3_4_2_1_2"/><i><font color="Green">E150</font></i>: 
( <font color="Maroon">z</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="borsuk_1.html#K6">[:</a><span class="default"><font color="Maroon">cT1</font>,<font color="Maroon">s</font></span><a href="borsuk_1.html#K6">:]</a></span> &amp; <font color="Maroon">s</font> <a href="hidden.html#R2">in</a> <font color="Maroon">bY</font> )
 ;<br/><a NAME="E4:59_3_4_2_1_2"/>
<font color="Maroon">p2</font> <a href="hidden.html#R2">in</a> <font color="Maroon">s</font>
 <b>by </b><i>, <a class="ref" href="yellow_9.html#T2" target="_self">Th2</a>, , <a class="ref" href="setfam_1.html#T58">SETFAM_1:58</a></i>;<br/><b>hence </b><a NAME="E5:59_3_4_2_1_2"/>
<span class="p1"><a href="borsuk_1.html#K7">[</a><span class="default"><font color="Maroon">p1</font>,<font color="Maroon">p2</font></span><a href="borsuk_1.html#K7">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">z</font>
 <b>by </b><i>, <a class="ref" href="zfmisc_1.html#T106">ZFMISC_1:106</a></i>;<br/></div><b>end;</b></div></div><b>end;</b></div></div><b>end;</b></div>
<b>hence </b><a NAME="E8:59_3_4"/>
<font color="Maroon">p</font> <a href="hidden.html#R2">in</a>  <a href="setfam_1.html#K8">Intersect</a> <font color="Maroon">Y</font>
 <b>by </b><i><a class="ref" href="yellow_9.html#T2" target="_self">Th2</a>, <a class="ref" href="setfam_1.html#T58">SETFAM_1:58</a></i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E22:59_3"/>
<font color="Maroon">d</font> <a href="hidden.html#R2">in</a>  <a href="cantor_1.html#K2">FinMeetCl</a> <font color="Maroon">C</font>
 <b>by </b><i>, , <a class="ref" href="cantor_1.html#D4">CANTOR_1:def 4</a></i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E18:59"/>
<span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default">the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T1</font>,<font color="Olive">b</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">b</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T2</font> : <font color="Olive">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B2</font> </span>}</span>  <a href="xboole_0.html#K2">\/</a> <span class="p1">{<span class="default"> <span class="p2"><a href="zfmisc_1.html#K2">[:</a><span class="default"><font color="Olive">a</font>,the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">T2</font></span><a href="zfmisc_1.html#K2">:]</a></span> where <font color="Olive">a</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T1</font> : <font color="Olive">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B1</font> </span>}</span>  is    <a href="cantor_1.html#M2">prebasis</a> of <span class="p1"><a href="borsuk_1.html#K5">[:</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="borsuk_1.html#K5">:]</a></span>
 ;<br/>


</div>
