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<span class="kw">consider </span><font color="Maroon" title="c4">a</font> being    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of <font color="Maroon" title="c1">I</font>;<br/>
<span class="kw">set </span><font color="Maroon" title="c5">X</font> = <span class="p1">{<span class="default"> <span class="p2"><a href="pralg_2.html#K6" title="PRALG_2:func.6">|.</a><span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c3">A</font> <a href="pralg_2.html#K5" title="PRALG_2:func.5">.</a> <font color="Olive" title="b1">i</font></span>)</span></span><a href="pralg_2.html#K6" title="PRALG_2:func.6">.|</a></span> where <font color="Olive" title="b1">i</font> is    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of <font color="Maroon" title="c1">I</font> : verum </span>}</span> ;<br/>
<a NAME="E2:21_1_1"/>
( <span class="p1"><a href="pralg_2.html#K6" title="PRALG_2:func.6">|.</a><span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c3">A</font> <a href="pralg_2.html#K5" title="PRALG_2:func.5">.</a> <font color="Maroon" title="c4">a</font></span>)</span></span><a href="pralg_2.html#K6" title="PRALG_2:func.6">.|</a></span> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <span class="p1">{<span class="default"> <span class="p2"><a href="pralg_2.html#K6" title="PRALG_2:func.6">|.</a><span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c3">A</font> <a href="pralg_2.html#K5" title="PRALG_2:func.5">.</a> <font color="Olive" title="b1">i</font></span>)</span></span><a href="pralg_2.html#K6" title="PRALG_2:func.6">.|</a></span> where <font color="Olive" title="b1">i</font> is    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of <font color="Maroon" title="c1">I</font> : verum </span>}</span>  &amp;  ex <font color="Olive" title="b1">x</font> being   <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a>  st <font color="Olive" title="b1">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <span class="p1"><a href="pralg_2.html#K6" title="PRALG_2:func.6">|.</a><span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c3">A</font> <a href="pralg_2.html#K5" title="PRALG_2:func.5">.</a> <font color="Maroon" title="c4">a</font></span>)</span></span><a href="pralg_2.html#K6" title="PRALG_2:func.6">.|</a></span> )
 
<span class="kw">by</span> <span class="lab"><a class="ref" href="xboole_0.html#D1" title="XBOOLE_0:def.1">XBOOLE_0:def 1</a></span>;<br/>
<span class="kw">hence </span><a NAME="E3:21_1_1"/>
not <span class="p1"><a href="pralg_2.html#K7" title="PRALG_2:func.7">|.</a><span class="default"><font color="Maroon" title="c3">A</font></span><a href="pralg_2.html#K7" title="PRALG_2:func.7">.|</a></span> is  <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a> 
 <span class="kw">by</span> <span class="lab"><a class="ref" href="tarski.html#D4" title="TARSKI:def.4">TARSKI:def 4</a></span>; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="Red">::  thesis: </font></span></a><span class="hide"> verum</span><br/>


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