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<span class="kw">let </span><font color="Maroon" title="c1">D</font> be   non  <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a>   <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="firebrick">::  thesis: </font></span></a><span class="hide">  for <font color="Olive" title="b1">B</font>, <font color="Olive" title="b2">A</font> being    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a>   st <font color="Olive" title="b1">B</font> is <font color="Maroon" title="c1">D</font> <a href="fomodel0.html#V3" title="FOMODEL0:attr.3">-prefix</a>  &amp; <font color="Olive" title="b2">A</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Olive" title="b1">B</font> holds <br/><font color="Olive" title="b2">A</font> is <font color="Maroon" title="c1">D</font> <a href="fomodel0.html#V3" title="FOMODEL0:attr.3">-prefix</a> </span><br/><span class="kw">let </span><font color="Maroon" title="c2">B</font>, <font color="Maroon" title="c3">A</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="firebrick">::  thesis: </font></span></a><span class="hide"> ( <font color="Maroon" title="c2">B</font> is <font color="Maroon" title="c1">D</font> <a href="fomodel0.html#V3" title="FOMODEL0:attr.3">-prefix</a>  &amp; <font color="Maroon" title="c3">A</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Maroon" title="c2">B</font> implies <font color="Maroon" title="c3">A</font> is <font color="Maroon" title="c1">D</font> <a href="fomodel0.html#V3" title="FOMODEL0:attr.3">-prefix</a>  )</span><br/>





<span class="kw">set </span><font color="Maroon" title="c4">f</font> = <font color="Maroon" title="c1">D</font> <a href="monoid_0.html#K11" title="MONOID_0:func.11">-concatenation</a> ;<br/>
<span class="kw">assume </span><a NAME="E1:61"/>
( <font color="Maroon" title="c2">B</font> is <font color="Maroon" title="c1">D</font> <a href="fomodel0.html#V3" title="FOMODEL0:attr.3">-prefix</a>  &amp; <font color="Maroon" title="c3">A</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Maroon" title="c2">B</font> )
 ; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="firebrick">::  thesis: </font></span></a><span class="hide"> <font color="Maroon" title="c3">A</font> is <font color="Maroon" title="c1">D</font> <a href="fomodel0.html#V3" title="FOMODEL0:attr.3">-prefix</a> </span><br/>

<a NAME="E2:61"/><span class="kw">then </span>
( <font color="Maroon" title="c2">B</font> is <font color="Maroon" title="c1">D</font> <a href="monoid_0.html#K11" title="MONOID_0:func.11">-concatenation</a>  <a href="fomodel0.html#V2" title="FOMODEL0:attr.2">-unambiguous</a>  &amp; <font color="Maroon" title="c3">A</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Maroon" title="c2">B</font> )
 
<span class="kw">by</span> <span class="lab"><a class="ref" href="fomodel0.html#D3" target="_self" title="FOMODEL0:def.3">DefPrefix</a></span>;<br/>
<a NAME="E3:61"/><span class="kw">then </span>
<font color="Maroon" title="c3">A</font> is <font color="Maroon" title="c1">D</font> <a href="monoid_0.html#K11" title="MONOID_0:func.11">-concatenation</a>  <a href="fomodel0.html#V2" title="FOMODEL0:attr.2">-unambiguous</a> 
 
<span class="kw">by</span> <span class="lab"><a class="txt" href="fomodel0.html#E19"><span class="lab"><font color="Green" title="E18">Lm13</font></span></a></span>;<br/>
<span class="kw">hence </span><a NAME="E4:61"/>
<font color="Maroon" title="c3">A</font> is <font color="Maroon" title="c1">D</font> <a href="fomodel0.html#V3" title="FOMODEL0:attr.3">-prefix</a> 
 <span class="kw">by</span> <span class="lab"><a class="ref" href="fomodel0.html#D3" target="_self" title="FOMODEL0:def.3">DefPrefix</a></span>; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="firebrick">::  thesis: </font></span></a><span class="hide"> verum</span><br/>


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