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<b>let </b><font color="Maroon">i1</font> be   <a href="int_1.html#NM1">Integer</a>;<br/><b>let </b><font color="Maroon">i2</font> be   <a href="int_1.html#NM1">Integer</a>;<br/><b>let </b><font color="Maroon">i5</font> be   <a href="int_1.html#NM1">Integer</a>;<br/>





<b>thus </b><a NAME="E1:45"/>
( <font color="Maroon">i1</font>,<font color="Maroon">i2</font> <a href="int_1.html#R1" target="_self">are_congruent_mod</a> <font color="Maroon">i5</font> implies <font color="Maroon">i1</font> <a href="xcmplx_0.html#K2">+</a> <font color="Maroon">i5</font>,<font color="Maroon">i2</font> <a href="int_1.html#R1" target="_self">are_congruent_mod</a> <font color="Maroon">i5</font> )
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="45_1"><b>proof </b></a><div class="add">

<b>assume </b><a NAME="E1:45_1"/>
<font color="Maroon">i1</font>,<font color="Maroon">i2</font> <a href="int_1.html#R1" target="_self">are_congruent_mod</a> <font color="Maroon">i5</font>
 ;<br/>

<b>then consider </b><font color="Maroon">i0</font> being   <a href="int_1.html#NM1">Integer</a><b> such that </b><br/><a NAME="E3:45_1"/><i><font color="Green">E21</font></i>: 
<font color="Maroon">i5</font> <a href="xcmplx_0.html#K3">*</a> <font color="Maroon">i0</font> <a href="hidden.html#R1">=</a> <font color="Maroon">i1</font> <a href="xcmplx_0.html#K6">-</a> <font color="Maroon">i2</font>
 <b>by </b><i/>;<br/>
<a NAME="E4:45_1"/>
<span class="p1">(<span class="default"><font color="Maroon">i5</font> <a href="xcmplx_0.html#K3">*</a> <font color="Maroon">i0</font></span>)</span> <a href="xcmplx_0.html#K2">+</a> <span class="p1">(<span class="default"><font color="Maroon">i5</font> <a href="xcmplx_0.html#K3">*</a> 1</span>)</span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">i1</font> <a href="xcmplx_0.html#K2">+</a> <font color="Maroon">i5</font></span>)</span> <a href="xcmplx_0.html#K6">-</a> <font color="Maroon">i2</font>
 
<b>by </b><i><a class="txt" href="int_1.html#E1"><i><font color="Green">Lemma20</font></i></a></i>;<br/>
<a NAME="E5:45_1"/><b>then </b>
( <font color="Maroon">i5</font> <a href="xcmplx_0.html#K3">*</a> <span class="p1">(<span class="default"><font color="Maroon">i0</font> <a href="xcmplx_0.html#K2">+</a> 1</span>)</span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">i1</font> <a href="xcmplx_0.html#K2">+</a> <font color="Maroon">i5</font></span>)</span> <a href="xcmplx_0.html#K6">-</a> <font color="Maroon">i2</font> &amp; <font color="Maroon">i0</font> <a href="xcmplx_0.html#K2">+</a> 1 is   <a href="int_1.html#NM1">Integer</a> )
 
;<br/>
<b>hence </b><a NAME="E6:45_1"/>
<font color="Maroon">i1</font> <a href="xcmplx_0.html#K2">+</a> <font color="Maroon">i5</font>,<font color="Maroon">i2</font> <a href="int_1.html#R1" target="_self">are_congruent_mod</a> <font color="Maroon">i5</font>
 <b>by </b><i/>;<br/>


</div><b>end;</b></div>

<b>assume </b><a NAME="E2:45"/>
<font color="Maroon">i1</font> <a href="xcmplx_0.html#K2">+</a> <font color="Maroon">i5</font>,<font color="Maroon">i2</font> <a href="int_1.html#R1" target="_self">are_congruent_mod</a> <font color="Maroon">i5</font>
 ;<br/>

<b>then consider </b><font color="Maroon">i0</font> being   <a href="int_1.html#NM1">Integer</a><b> such that </b><br/><a NAME="E4:45"/><i><font color="Green">E22</font></i>: 
<font color="Maroon">i5</font> <a href="xcmplx_0.html#K3">*</a> <font color="Maroon">i0</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">i1</font> <a href="xcmplx_0.html#K2">+</a> <font color="Maroon">i5</font></span>)</span> <a href="xcmplx_0.html#K6">-</a> <font color="Maroon">i2</font>
 <b>by </b><i/>;<br/>
<a NAME="E5:45"/>
<span class="p1">(<span class="default"><font color="Maroon">i5</font> <a href="xcmplx_0.html#K3">*</a> <font color="Maroon">i0</font></span>)</span> <a href="xcmplx_0.html#K6">-</a> <span class="p1">(<span class="default"><font color="Maroon">i5</font> <a href="xcmplx_0.html#K3">*</a> 1</span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">i1</font> <a href="xcmplx_0.html#K6">-</a> <font color="Maroon">i2</font>
 
<b>by </b><i><a class="txt" href="int_1.html#E1"><i><font color="Green">Lemma20</font></i></a></i>;<br/>
<a NAME="E6:45"/><b>then </b>
( <font color="Maroon">i5</font> <a href="xcmplx_0.html#K3">*</a> <span class="p1">(<span class="default"><font color="Maroon">i0</font> <a href="xcmplx_0.html#K6">-</a> 1</span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">i1</font> <a href="xcmplx_0.html#K6">-</a> <font color="Maroon">i2</font> &amp; <font color="Maroon">i0</font> <a href="xcmplx_0.html#K6">-</a> 1 is   <a href="int_1.html#NM1">Integer</a> )
 
;<br/>
<b>hence </b><a NAME="E7:45"/>
<font color="Maroon">i1</font>,<font color="Maroon">i2</font> <a href="int_1.html#R1" target="_self">are_congruent_mod</a> <font color="Maroon">i5</font>
 <b>by </b><i/>;<br/>


</div>
