<?xml version="1.0"?>
<div class="add">

<b>let </b><font color="Maroon">c<sub>1</sub></font> be   <a href="subset_1.html#NM2">Subset</a> of <a href="intpro_1.html#K1" target="_self">MC-wff</a> ;<br/>

<b>assume </b><a NAME="E1:147"/><i><font color="Green">E108</font></i>: 
<font color="Maroon">c<sub>1</sub></font> is <a href="intpro_1.html#V10" target="_self">S4_theory</a>
 ;<br/>

<a NAME="E2:147"/>
 <a href="subset_1.html#K1">{}</a> <a href="intpro_1.html#K1" target="_self">MC-wff</a>  <a href="tarski.html#R1">c=</a> <font color="Maroon">c<sub>1</sub></font>
 
<b>by </b><i><a class="ref" href="xboole_1.html#T2">XBOOLE_1:2</a></i>;<br/>
<a NAME="E3:147"/><b>then </b>
 <a href="intpro_1.html#K14" target="_self">S4-Taut</a>  <a href="tarski.html#R1">c=</a>  <a href="intpro_1.html#K13" target="_self">CnS4</a> <font color="Maroon">c<sub>1</sub></font>
 
<b>by </b><i><a class="ref" href="intpro_1.html#T90" target="_self">Th90</a></i>;<br/>
<b>hence </b><a NAME="E4:147"/>
 <a href="intpro_1.html#K14" target="_self">S4-Taut</a>  <a href="tarski.html#R1">c=</a> <font color="Maroon">c<sub>1</sub></font>
 <b>by </b><i><a class="txt" href="intpro_1.html#E1:147"><i><font color="Green">E108</font></i></a>, <a class="ref" href="intpro_1.html#T92" target="_self">Th92</a></i>;<br/>


</div>
