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

<b>let </b><font color="Maroon">OAlph</font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">IAlph</font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">tfsm</font> be  non <a href="struct_0.html#V3">empty</a>  <a href="fsm_1.html#L2" target="_self">Mealy-FSM</a> of <font color="Maroon">IAlph</font>,<font color="Maroon">OAlph</font>;<br/><b>let </b><font color="Maroon">qa</font> be   <a href="fsm_1.html#NM1">State</a> of <font color="Maroon">tfsm</font>;<br/><b>let </b><font color="Maroon">qb</font> be   <a href="fsm_1.html#NM1">State</a> of <font color="Maroon">tfsm</font>;<br/>









<b>assume </b><a NAME="E1:51"/><i><font color="Green">E22</font></i>: 
<font color="Maroon">qa</font>,<font color="Maroon">qb</font> <a href="fsm_1.html#R5" target="_self">-are_equivalent</a> 
 ;<br/>

<b>let </b><font color="Maroon">w</font> be    <a href="finseq_1.html#M2">FinSequence</a> of <font color="Maroon">IAlph</font>;<br/>

<b>defpred </b><font color="Maroon">S<sub>1</sub></font>[   <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a> ] <b>means </b>( <font color="Maroon">a<sub>1</sub></font> <a href="hidden.html#R2">in</a>  <a href="finseq_1.html#K2">Seg</a> <span class="p1">(<span class="default"><a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font></span>)</span> implies  ex <font color="Olive">qai</font>, <font color="Olive">qbi</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">tfsm</font> st <br/>( <font color="Olive">qai</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qa</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">a<sub>1</sub></font> &amp; <font color="Olive">qbi</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qb</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">a<sub>1</sub></font> &amp; <font color="Olive">qai</font>,<font color="Olive">qbi</font> <a href="fsm_1.html#R5" target="_self">-are_equivalent</a>  ) );<br/>
<a NAME="E2:51"/><i><font color="Green">E23</font></i>: 
<font color="Maroon">S<sub>1</sub></font>[0]
 
<b>by </b><i><a class="ref" href="finseq_1.html#T3">FINSEQ_1:3</a></i>;<br/>
<a NAME="E3:51"/><i><font color="Green">E38</font></i>: 
for <font color="Olive">i</font> being   <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a>   st <font color="Maroon">S<sub>1</sub></font>[<font color="Olive">i</font>] holds <br/><font color="Maroon">S<sub>1</sub></font>[<font color="Olive">i</font> <a href="nat_1.html#K1">+</a> 1]
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="51_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">i</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a> ;<br/>

<b>assume </b><a NAME="E1:51_1"/><i><font color="Green">E39</font></i>: 
( <font color="Maroon">i</font> <a href="hidden.html#R2">in</a>  <a href="finseq_1.html#K2">Seg</a> <span class="p1">(<span class="default"><a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font></span>)</span> implies  ex <font color="Olive">qai</font>, <font color="Olive">qbi</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">tfsm</font> st <br/>( <font color="Olive">qai</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qa</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font> &amp; <font color="Olive">qbi</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qb</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font> &amp; <font color="Olive">qai</font>,<font color="Olive">qbi</font> <a href="fsm_1.html#R5" target="_self">-are_equivalent</a>  ) )
 ;<br/>

<b>assume </b><a NAME="E2:51_1"/>
<font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1 <a href="hidden.html#R2">in</a>  <a href="finseq_1.html#K2">Seg</a> <span class="p1">(<span class="default"><a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font></span>)</span>
 ;<br/>

<a NAME="E3:51_1"/><b>then </b><i><font color="Green">E40</font></i>: 
( 1 <a href="xxreal_0.html#R1">&lt;=</a> <font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1 &amp; <font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1 <a href="xxreal_0.html#R1">&lt;=</a>  <a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font> )
 
<b>by </b><i><a class="ref" href="finseq_1.html#T3">FINSEQ_1:3</a></i>;<br/>
<a NAME="E4:51_1"/>
( <font color="Maroon">i</font> <a href="hidden.html#R1">=</a> 0 or ( 0 <a href="xxreal_0.html#NR3" target="_self">&lt;</a> <font color="Maroon">i</font> &amp; 0 <a href="nat_1.html#K1">+</a> 1 <a href="hidden.html#R1">=</a> 1 ) )
 
;<br/>
<a NAME="E5:51_1"/><b>then </b><i><font color="Green">E42</font></i>: 
( 0 <a href="hidden.html#R1">=</a> <font color="Maroon">i</font> or ( 1 <a href="xxreal_0.html#R1">&lt;=</a> <font color="Maroon">i</font> &amp; <font color="Maroon">i</font> <a href="xxreal_0.html#R1">&lt;=</a>  <a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font> ) )
 
<b>by </b><i>, <a class="ref" href="nat_1.html#T38">NAT_1:38</a></i>;<br/>
<div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="51_1_1"><b>per </b></a><a class="txt" onclick="hs(this)" href="javascript:()"><b>cases </b></a><span class="hide"><a NAME="E1:51_1_1"/>
( <font color="Maroon">i</font> <a href="hidden.html#R1">=</a> 0 or <font color="Maroon">i</font> <a href="hidden.html#R2">in</a>  <a href="finseq_1.html#K2">Seg</a> <span class="p1">(<span class="default"><a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font></span>)</span> )
 </span><b>by </b><i><a class="txt" href="fsm_1.html#E3:51"><i><font color="Green">E38</font></i></a>, <a class="ref" href="finseq_1.html#T3">FINSEQ_1:3</a></i>;<br/><div class="add"><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="51_1_1_1"><b>suppose </b></a><a NAME="E1:51_1_1_1"/><i><font color="Green">E43</font></i>: 
<font color="Maroon">i</font> <a href="hidden.html#R1">=</a> 0
 ;<br/><div class="add"><b>reconsider </b><font color="Maroon">qai</font> = <span class="p1">(<span class="default"><font color="Maroon">qa</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> 1, <font color="Maroon">qbi</font> = <span class="p1">(<span class="default"><font color="Maroon">qb</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> 1 as   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">tfsm</font> <b>by </b><i/>;<br/><b>take </b>
<font color="Maroon">qai</font>
;<br/><b>take </b>
<font color="Maroon">qbi</font>
;<br/><a NAME="E3:51_1_1_1"/><i><font color="Green">E44</font></i>: 
<font color="Maroon">qai</font> <a href="hidden.html#R1">=</a> <font color="Maroon">qa</font>
 <b>by </b><i/>;<br/><b>thus </b><a NAME="E4:51_1_1_1"/>
<font color="Maroon">qai</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qa</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1</span>)</span>
 <b>by </b><i><a class="txt" href="fsm_1.html#E1:51_1"><i><font color="Green">E39</font></i></a></i>;<br/><b>thus </b><a NAME="E5:51_1_1_1"/>
<font color="Maroon">qbi</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qb</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1</span>)</span>
 <b>by </b><i><a class="txt" href="fsm_1.html#E1:51_1"><i><font color="Green">E39</font></i></a></i>;<br/><b>thus </b><a NAME="E6:51_1_1_1"/>
<font color="Maroon">qai</font>,<font color="Maroon">qbi</font> <a href="fsm_1.html#R5" target="_self">-are_equivalent</a> 
 <b>by </b><i>, <a class="txt" href="fsm_1.html#E3:51_1"><i><font color="Green">E40</font></i></a>, </i>;<br/></div><b>end;</b></div><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="51_1_1_2"><b>suppose </b></a><a NAME="E1:51_1_1_2"/><i><font color="Green">E45</font></i>: 
<font color="Maroon">i</font> <a href="hidden.html#R2">in</a>  <a href="finseq_1.html#K2">Seg</a> <span class="p1">(<span class="default"><a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font></span>)</span>
 ;<br/><div class="add"><b>then consider </b><font color="Maroon">qai</font> being   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">tfsm</font>, <font color="Maroon">qbi</font> being   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">tfsm</font><b> such that </b><br/><a NAME="E3:51_1_1_2"/><i><font color="Green">E46</font></i>: 
( <font color="Maroon">qai</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qa</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font> &amp; <font color="Maroon">qbi</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qb</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font> &amp; <font color="Maroon">qai</font>,<font color="Maroon">qbi</font> <a href="fsm_1.html#R5" target="_self">-are_equivalent</a>  )
 <b>by </b><i/>;<br/><a NAME="E4:51_1_1_2"/><i><font color="Green">E47</font></i>: 
( 1 <a href="xxreal_0.html#R1">&lt;=</a> <font color="Maroon">i</font> &amp; <font color="Maroon">i</font> <a href="xxreal_0.html#R1">&lt;=</a>  <a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font> )
 <b>by </b><i><a class="txt" href="fsm_1.html#E1:51_1"><i><font color="Green">E39</font></i></a>, <a class="ref" href="finseq_1.html#T3">FINSEQ_1:3</a></i>;<br/><b>then consider </b><font color="Maroon">wi</font> being    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">IAlph</font>, <font color="Maroon">qai'</font> being   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">tfsm</font>, <font color="Maroon">qai1'</font> being   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">tfsm</font><b> such that </b><br/><a NAME="E6:51_1_1_2"/><i><font color="Green">E79</font></i>: 
( <font color="Maroon">wi</font> <a href="hidden.html#R1">=</a> <font color="Maroon">w</font> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font> &amp; <font color="Maroon">qai'</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qa</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font> &amp; <font color="Maroon">qai1'</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qa</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1</span>)</span> &amp; <font color="Maroon">wi</font> <a href="fsm_1.html#K1" target="_self">-succ_of</a> <font color="Maroon">qai'</font> <a href="hidden.html#R1">=</a> <font color="Maroon">qai1'</font> )
 <b>by </b><i/>;<br/><b>consider </b><font color="Maroon">wi'</font> being    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">IAlph</font>, <font color="Maroon">qbi'</font> being   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">tfsm</font>, <font color="Maroon">qbi1'</font> being   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">tfsm</font><b> such that </b><br/><a NAME="E8:51_1_1_2"/><i><font color="Green">E81</font></i>: 
( <font color="Maroon">wi'</font> <a href="hidden.html#R1">=</a> <font color="Maroon">w</font> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font> &amp; <font color="Maroon">qbi'</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qb</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font> &amp; <font color="Maroon">qbi1'</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qb</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1</span>)</span> &amp; <font color="Maroon">wi'</font> <a href="fsm_1.html#K1" target="_self">-succ_of</a> <font color="Maroon">qbi'</font> <a href="hidden.html#R1">=</a> <font color="Maroon">qbi1'</font> )
 <b>by </b><i>, </i>;<br/><b>take </b>
<font color="Maroon">qai1'</font>
;<br/><b>take </b>
<font color="Maroon">qbi1'</font>
;<br/><b>thus </b><a NAME="E9:51_1_1_2"/>
<font color="Maroon">qai1'</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qa</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1</span>)</span>
 <b>by </b><i><a class="txt" href="fsm_1.html#E5:51_1"><i><font color="Green">E42</font></i></a></i>;<br/><b>thus </b><a NAME="E10:51_1_1_2"/>
<font color="Maroon">qbi1'</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qb</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1</span>)</span>
 <b>by </b><i/>;<br/><b>thus </b><a NAME="E11:51_1_1_2"/>
<font color="Maroon">qai1'</font>,<font color="Maroon">qbi1'</font> <a href="fsm_1.html#R5" target="_self">-are_equivalent</a> 
 <b>by </b><i><a class="txt" href="fsm_1.html#E3:51_1"><i><font color="Green">E40</font></i></a>, <a class="txt" href="fsm_1.html#E5:51_1"><i><font color="Green">E42</font></i></a>, , </i>;<br/></div><b>end;</b></div></div><b>end;</b></div>

</div><b>end;</b></div>
<a NAME="E4:51"/><i><font color="Green">E82</font></i>: 
 <a href="finseq_1.html#K2">Seg</a> <span class="p1">(<span class="default"><a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="finseq_1.html#K4">dom</a> <font color="Maroon">w</font>
 
<b>by </b><i><a class="ref" href="finseq_1.html#D3">FINSEQ_1:def 3</a></i>;<br/>
<a NAME="E5:51"/>
for <font color="Olive">i</font> being   <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a>  holds  <font color="Maroon">S<sub>1</sub></font>[<font color="Olive">i</font>]
 
<b>from </b><i><a class="ref" href="nat_1.html#S1">NAT_1:sch 1</a>(, );<br/></i>
<b>hence </b><a NAME="E6:51"/>
for <font color="Olive">i</font> being   <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a>   st <font color="Olive">i</font> <a href="hidden.html#R2">in</a>  <a href="finseq_1.html#K4">dom</a> <font color="Maroon">w</font> holds <br/> ex <font color="Olive">qai</font>, <font color="Olive">qbi</font> being  <a href="fsm_1.html#NM1">State</a> of <font color="Maroon">tfsm</font> st <br/>( <font color="Olive">qai</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qa</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Olive">i</font> &amp; <font color="Olive">qbi</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">qb</font>,<font color="Maroon">w</font> <a href="fsm_1.html#K2" target="_self">-admissible</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Olive">i</font> &amp; <font color="Olive">qai</font>,<font color="Olive">qbi</font> <a href="fsm_1.html#R5" target="_self">-are_equivalent</a>  )
 <b>by </b><i/>;<br/>


</div>
