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

<b>thus </b><a NAME="E1:1_1_1"/>
(  <a href="zf_lang.html#K2">x.</a> 0 <a href="hidden.html#R2">in</a>  <a href="zf_fund1.html#K6">Free</a> <font color="Maroon">H</font> implies <span class="p1">{<span class="default"> <font color="Olive">m</font> where <font color="Olive">m</font> is    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">M</font> : <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_lang1.html#K1">/</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K2">x.</a> 0</span>)</span>,<font color="Olive">m</font> <a href="zf_model.html#R1">|=</a> <font color="Maroon">H</font> </span>}</span>  is   <a href="subset_1.html#NM2">Subset</a> of <font color="Maroon">M</font> )
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="1_1_1_1"><b>proof </b></a><div class="add">

<b>assume </b><a NAME="E1:1_1_1_1"/>
 <a href="zf_lang.html#K2">x.</a> 0 <a href="hidden.html#R2">in</a>  <a href="zf_fund1.html#K6">Free</a> <font color="Maroon">H</font>
 ;<br/>

<b>set </b><font color="Maroon">X</font> = <span class="p1">{<span class="default"> <font color="Olive">m</font> where <font color="Olive">m</font> is    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">M</font> : <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_lang1.html#K1">/</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K2">x.</a> 0</span>)</span>,<font color="Olive">m</font> <a href="zf_model.html#R1">|=</a> <font color="Maroon">H</font> </span>}</span> ;<br/>
<a NAME="E2:1_1_1_1"/>
<span class="p1">{<span class="default"> <font color="Olive">m</font> where <font color="Olive">m</font> is    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">M</font> : <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_lang1.html#K1">/</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K2">x.</a> 0</span>)</span>,<font color="Olive">m</font> <a href="zf_model.html#R1">|=</a> <font color="Maroon">H</font> </span>}</span>  <a href="tarski.html#R1">c=</a> <font color="Maroon">M</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="1_1_1_1_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">u</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="E1:1_1_1_1_1"/>
<font color="Maroon">u</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <font color="Olive">m</font> where <font color="Olive">m</font> is    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">M</font> : <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_lang1.html#K1">/</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K2">x.</a> 0</span>)</span>,<font color="Olive">m</font> <a href="zf_model.html#R1">|=</a> <font color="Maroon">H</font> </span>}</span> 
 ;<br/>

<a NAME="E2:1_1_1_1_1"/><b>then </b>
 ex <font color="Olive">m</font> being   <a href="subset_1.html#M1">Element</a> of <font color="Maroon">M</font> st <br/>( <font color="Maroon">u</font> <a href="hidden.html#R1">=</a> <font color="Olive">m</font> &amp; <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_lang1.html#K1">/</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K2">x.</a> 0</span>)</span>,<font color="Olive">m</font> <a href="zf_model.html#R1">|=</a> <font color="Maroon">H</font> )
 
;<br/>
<b>hence </b><a NAME="E3:1_1_1_1_1"/>
<font color="Maroon">u</font> <a href="hidden.html#R2">in</a> <font color="Maroon">M</font>
 ;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E3:1_1_1_1"/>
<span class="p1">{<span class="default"> <font color="Olive">m</font> where <font color="Olive">m</font> is    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">M</font> : <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_lang1.html#K1">/</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K2">x.</a> 0</span>)</span>,<font color="Olive">m</font> <a href="zf_model.html#R1">|=</a> <font color="Maroon">H</font> </span>}</span>  is   <a href="subset_1.html#NM2">Subset</a> of <font color="Maroon">M</font>
 ;<br/>


</div><b>end;</b></div>

<b>thus </b><a NAME="E2:1_1_1"/>
( not  <a href="zf_lang.html#K2">x.</a> 0 <a href="hidden.html#R2">in</a>  <a href="zf_fund1.html#K6">Free</a> <font color="Maroon">H</font> implies  <a href="xboole_0.html#K1">{}</a>  is   <a href="subset_1.html#NM2">Subset</a> of <font color="Maroon">M</font> )
 <b>by </b><i><a class="ref" href="xboole_1.html#T2">XBOOLE_1:2</a></i>;<br/>


</div>
