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<b>let </b><font color="Maroon" title="c1">A</font>, <font color="Maroon" title="c2">X</font>, <font color="Maroon" title="c3">B</font>, <font color="Maroon" title="c4">Y</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/>







<b>assume </b><b>that </b><br/><a NAME="E1:63"/><i><font color="Green" title="E34">A1</font></i>: 
<font color="Maroon" title="c1">A</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Maroon" title="c2">X</font>
 <b>and </b><br/><a NAME="E2:63"/><i><font color="Green" title="E35">A2</font></i>: 
<font color="Maroon" title="c3">B</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Maroon" title="c4">Y</font>
 <b>and </b><br/><a NAME="E3:63"/><i><font color="Green" title="E36">A3</font></i>: 
<font color="Maroon" title="c2">X</font> <a href="xboole_0.html#R1" title="XBOOLE_0:pred.1">misses</a> <font color="Maroon" title="c4">Y</font>
 ;<br/>

<a NAME="E4:63"/>
<font color="Maroon" title="c1">A</font> <a href="xboole_0.html#R1" title="XBOOLE_0:pred.1">misses</a> <font color="Maroon" title="c4">Y</font>
 
<b>by </b><i><a class="txt" href="xboole_1.html#E1:63"><i><font color="Green" title="E34">A1</font></i></a>, <a class="txt" href="xboole_1.html#E3:63"><i><font color="Green" title="E36">A3</font></i></a>, <a class="ref" href="xboole_1.html#T63" target="_self" title="XBOOLE_1:th.63">Th63</a></i>;<br/>
<b>hence </b><a NAME="E5:63"/>
<font color="Maroon" title="c1">A</font> <a href="xboole_0.html#R1" title="XBOOLE_0:pred.1">misses</a> <font color="Maroon" title="c3">B</font>
 <b>by </b><i><a class="txt" href="xboole_1.html#E2:63"><i><font color="Green" title="E35">A2</font></i></a>, <a class="ref" href="xboole_1.html#T63" target="_self" title="XBOOLE_1:th.63">Th63</a></i>;<br/>


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