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<b>let </b><font color="Maroon">c<sub>2</sub></font>, <font color="Maroon">c<sub>3</sub></font> be  <a href="lang1.html#V2" target="_self">strict</a>  <a href="lang1.html#L2" target="_self">GrammarStr</a> ;<br/>

<b>assume </b><b>that </b><br/><a NAME="E1:25_1_2"/><i><font color="Green">E9</font></i>: 
( the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">c<sub>1</sub></font></span><a href="tarski.html#K1">}</a></span> &amp; the <a href="lang1.html#U1" target="_self">Rules</a> of <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><span class="p2"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">c<sub>1</sub></font>,<a href="xboole_0.html#K1">{}</a> </span><a href="tarski.html#K4">]</a></span></span><a href="tarski.html#K1">}</a></span> )
 <b>and </b><br/><a NAME="E2:25_1_2"/><i><font color="Green">E10</font></i>: 
( the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">c<sub>3</sub></font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">c<sub>1</sub></font></span><a href="tarski.html#K1">}</a></span> &amp; the <a href="lang1.html#U1" target="_self">Rules</a> of <font color="Maroon">c<sub>3</sub></font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><span class="p2"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">c<sub>1</sub></font>,<a href="xboole_0.html#K1">{}</a> </span><a href="tarski.html#K4">]</a></span></span><a href="tarski.html#K1">}</a></span> )
 ;<br/>

<a NAME="E3:25_1_2"/>
( the <a href="lang1.html#U2" target="_self">InitialSym</a> of <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>1</sub></font> &amp; the <a href="lang1.html#U2" target="_self">InitialSym</a> of <font color="Maroon">c<sub>3</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>1</sub></font> &amp; <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a>  <a href="lang1.html#G2" target="_self">GrammarStr</a>(# the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">c<sub>2</sub></font>,the <a href="lang1.html#U2" target="_self">InitialSym</a> of <font color="Maroon">c<sub>2</sub></font>,the <a href="lang1.html#U1" target="_self">Rules</a> of <font color="Maroon">c<sub>2</sub></font> #) &amp; <font color="Maroon">c<sub>3</sub></font> <a href="hidden.html#R1">=</a>  <a href="lang1.html#G2" target="_self">GrammarStr</a>(# the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">c<sub>3</sub></font>,the <a href="lang1.html#U2" target="_self">InitialSym</a> of <font color="Maroon">c<sub>3</sub></font>,the <a href="lang1.html#U1" target="_self">Rules</a> of <font color="Maroon">c<sub>3</sub></font> #) )
 
<b>by </b><i><a class="txt" href="lang1.html#E1:25_1_2"><i><font color="Green">E9</font></i></a>, <a class="txt" href="lang1.html#E2:25_1_2"><i><font color="Green">E10</font></i></a>, <a class="ref" href="tarski.html#D1">TARSKI:def 1</a></i>;<br/>
<b>hence </b><a NAME="E4:25_1_2"/>
<font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>3</sub></font>
 <b>by </b><i><a class="txt" href="lang1.html#E1:25_1_2"><i><font color="Green">E9</font></i></a>, <a class="txt" href="lang1.html#E2:25_1_2"><i><font color="Green">E10</font></i></a></i>;<br/>


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