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<b>let </b><font color="Maroon">P</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">N</font> be    <a href="pnproc_1.html#M3" target="_self">Petri_net</a> of <font color="Maroon">P</font>;<br/><b>let </b><font color="Maroon">R1</font> be   <a href="pnproc_1.html#NM6">process</a> of <font color="Maroon">N</font>;<br/><b>let </b><font color="Maroon">P1</font> be   <a href="pnproc_1.html#NM6">process</a> of <font color="Maroon">N</font>;<br/><b>let </b><font color="Maroon">R2</font> be   <a href="pnproc_1.html#NM6">process</a> of <font color="Maroon">N</font>;<br/><b>let </b><font color="Maroon">P2</font> be   <a href="pnproc_1.html#NM6">process</a> of <font color="Maroon">N</font>;<br/>











<b>assume </b><a NAME="E1:101"/><i><font color="Green">E29</font></i>: 
( <font color="Maroon">R1</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">P1</font> &amp; <font color="Maroon">R2</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">P2</font> )
 ;<br/>

<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a><br/>

<b>assume </b><a NAME="E2:101"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">R1</font> <a href="pnproc_1.html#K12" target="_self">before</a> <font color="Maroon">R2</font>
 ;<br/>

<b>then consider </b><font color="Maroon">C1</font> being   <a href="pnproc_1.html#NM5">firing-sequence</a> of <font color="Maroon">N</font>, <font color="Maroon">C2</font> being   <a href="pnproc_1.html#NM5">firing-sequence</a> of <font color="Maroon">N</font><b> such that </b><br/><a NAME="E4:101"/><i><font color="Green">E30</font></i>: 
( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Maroon">C1</font> <a href="lang1.html#K1">^</a> <font color="Maroon">C2</font> &amp; <font color="Maroon">C1</font> <a href="hidden.html#R2">in</a> <font color="Maroon">R1</font> &amp; <font color="Maroon">C2</font> <a href="hidden.html#R2">in</a> <font color="Maroon">R2</font> )
 ;<br/>
<b>thus </b><a NAME="E5:101"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">P1</font> <a href="pnproc_1.html#K12" target="_self">before</a> <font color="Maroon">P2</font>
 <b>by </b><i><a class="ref" href="pnproc_1.html#D1" target="_self">Def1</a>, </i>;<br/>


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