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<b>let </b><font color="Maroon">f</font> be   <a href="funct_1.html#NM1">Function</a>, <font color="Maroon">g</font> be   <a href="funct_1.html#NM1">Function</a>, <font color="Maroon">h</font> be   <a href="funct_1.html#NM1">Function</a>;<br/>

<b>assume </b><a NAME="E1:1"/>
( <font color="Maroon">f</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">h</font> &amp; <font color="Maroon">g</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">h</font> )
 ;<br/>

<a NAME="E2:1"/><b>then </b><i><font color="Green">E29</font></i>: 
<font color="Maroon">f</font> <a href="xboole_0.html#K2">\/</a> <font color="Maroon">g</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">h</font>
 
<b>by </b><i><a class="ref" href="xboole_1.html#T8">XBOOLE_1:8</a></i>;<br/>
<a NAME="E3:1"/>
<font color="Maroon">f</font> <a href="funct_4.html#K1">+*</a> <font color="Maroon">g</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">f</font> <a href="xboole_0.html#K2">\/</a> <font color="Maroon">g</font>
 
<b>by </b><i><a class="ref" href="funct_4.html#T30">FUNCT_4:30</a></i>;<br/>
<b>hence </b><a NAME="E4:1"/>
<font color="Maroon">f</font> <a href="funct_4.html#K1">+*</a> <font color="Maroon">g</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">h</font>
 <b>by </b><i>, <a class="ref" href="xboole_1.html#T1">XBOOLE_1:1</a></i>;<br/>


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