<?xml version="1.0"?>
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<b>let </b><font color="Maroon">X</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">Y</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">f</font> be   <a href="funct_1.html#NM1">Function</a>;<br/>





<b>assume </b><a NAME="E1:68"/>
<font color="Maroon">f</font> is <a href="funct_1.html#V2">one-to-one</a>
 ;<br/>

<a NAME="E2:68"/><b>then </b>
<font color="Maroon">Y</font> <a href="relat_1.html#K8">|</a> <font color="Maroon">f</font> is <a href="funct_1.html#V2">one-to-one</a>
 
<b>by </b><i><a class="ref" href="funct_1.html#T99">FUNCT_1:99</a></i>;<br/>
<a NAME="E3:68"/><b>then </b>
<span class="p1">(<span class="default"><font color="Maroon">Y</font> <a href="relat_1.html#K8">|</a> <font color="Maroon">f</font></span>)</span> <a href="relat_1.html#K7">|</a> <font color="Maroon">X</font> is <a href="funct_1.html#V2">one-to-one</a>
 
<b>by </b><i><a class="ref" href="funct_1.html#T84">FUNCT_1:84</a></i>;<br/>
<b>hence </b><a NAME="E4:68"/>
<span class="p1"><a href="partfun1.html#K3" target="_self">&lt;:</a><span class="default"><font color="Maroon">f</font>,<font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="partfun1.html#K3" target="_self">:&gt;</a></span> is <a href="funct_1.html#V2">one-to-one</a>
 ;<br/>


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