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<b>reconsider </b><font color="Maroon" title="c3">h</font> =  <a href="xboole_0.html#K1" title="XBOOLE_0:func.1">{}</a>  as   <a href="partfun1.html#NM1" title="PARTFUN1:NM.1">PartFunc</a> of <font color="Maroon" title="c1">X</font>,<font color="Maroon" title="c2">Y</font> <b>by </b><i><a class="ref" href="partfun1.html#T56" title="PARTFUN1:th.56">PARTFUN1:56</a></i>;<br/>
<a NAME="E2:19_1_1"/>
<span class="p1"><a href="tarski.html#K1" title="TARSKI:func.1">{</a><span class="default"><font color="Maroon" title="c3">h</font></span><a href="tarski.html#K1" title="TARSKI:func.1">}</a></span> is    <a href="rfunct_3.html#M1" title="RFUNCT_3:mode.1">PartFunc-set</a> of <font color="Maroon" title="c1">X</font>,<font color="Maroon" title="c2">Y</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="19_1_1_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon" title="c4">x</font> be    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of <span class="p1"><a href="tarski.html#K1" title="TARSKI:func.1">{</a><span class="default"><font color="Maroon" title="c3">h</font></span><a href="tarski.html#K1" title="TARSKI:func.1">}</a></span>; <i><font color="Red">:: according to </font></i><a class="ref" href="rfunct_3.html#D3" target="_self" title="RFUNCT_3:def.3">RFUNCT_3:def 3</a><br/>

<b>thus </b><a NAME="E1:19_1_1_1"/>
<font color="Maroon" title="c4">x</font> is   <a href="partfun1.html#NM1" title="PARTFUN1:NM.1">PartFunc</a> of <font color="Maroon" title="c1">X</font>,<font color="Maroon" title="c2">Y</font>
 <b>by </b><i><a class="ref" href="tarski.html#D1" title="TARSKI:def.1">TARSKI:def 1</a></i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E3:19_1_1"/>
not for <font color="Olive">b<sub>1</sub></font> being   <a href="rfunct_3.html#M1" title="RFUNCT_3:mode.1">PartFunc-set</a> of <font color="Maroon" title="c1">X</font>,<font color="Maroon" title="c2">Y</font> holds  <font color="Olive">b<sub>1</sub></font> is <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a>
 ;<br/>


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