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<b>let </b><font color="Maroon">c<sub>1</sub></font> be   <a href="rat_1.html#NM1">Rational</a>;<br/>

<b>set </b><font color="Maroon">c<sub>2</sub></font> =  <a href="rat_1.html#K2">numerator</a> <font color="Maroon">c<sub>1</sub></font>;<br/>
<b>set </b><font color="Maroon">c<sub>3</sub></font> =  <a href="rat_1.html#K1">denominator</a> <font color="Maroon">c<sub>1</sub></font>;<br/>
<a NAME="E1:60"/><i><font color="Green">E43</font></i>: 
 <a href="rat_1.html#K1">denominator</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> 0
 
<b>by </b><i><a class="ref" href="rat_1.html#D3">RAT_1:def 3</a></i>;<br/>
<b>assume </b><a NAME="E2:60"/><i><font color="Green">E44</font></i>: 
not  <a href="rat_1.html#K2">numerator</a> <font color="Maroon">c<sub>1</sub></font>, <a href="rat_1.html#K1">denominator</a> <font color="Maroon">c<sub>1</sub></font> <a href="int_2.html#R1">are_relative_prime</a> 
 ;<br/>

<b>reconsider </b><font color="Maroon">c<sub>4</sub></font> = <span class="p1">(<span class="default"><a href="rat_1.html#K2">numerator</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> <a href="int_2.html#K3">gcd</a> <span class="p1">(<span class="default"><a href="rat_1.html#K1">denominator</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> as   <a href="nat_1.html#NM1">Nat</a> <b>by </b><i><a class="ref" href="int_2.html#T29">INT_2:29</a></i>;<br/>
<a NAME="E4:60"/><i><font color="Green">E45</font></i>: 
<font color="Maroon">c<sub>4</sub></font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> 1
 
<b>by </b><i><a class="txt" href="wsierp_1.html#E2:60"><i><font color="Green">E44</font></i></a>, <a class="ref" href="int_2.html#D4">INT_2:def 4</a></i>;<br/>
<a NAME="E5:60"/>
<font color="Maroon">c<sub>4</sub></font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> 0
 
<b>by </b><i><a class="txt" href="wsierp_1.html#E1:60"><i><font color="Green">E43</font></i></a>, <a class="ref" href="int_2.html#T35">INT_2:35</a></i>;<br/>
<a NAME="E6:60"/><b>then </b>
<font color="Maroon">c<sub>4</sub></font> <a href="xxreal_0.html#NR4" target="_self">&gt;</a> 0
 
;<br/>
<a NAME="E7:60"/><b>then </b>
<font color="Maroon">c<sub>4</sub></font> <a href="xxreal_0.html#NR2" target="_self">&gt;=</a> 0 <a href="nat_1.html#K1">+</a> 1
 
<b>by </b><i><a class="ref" href="nat_1.html#T38">NAT_1:38</a></i>;<br/>
<a NAME="E8:60"/><b>then </b><i><font color="Green">E46</font></i>: 
<font color="Maroon">c<sub>4</sub></font> <a href="xxreal_0.html#NR4" target="_self">&gt;</a> 1
 
<b>by </b><i><a class="txt" href="wsierp_1.html#E4:60"><i><font color="Green">E45</font></i></a>, <a class="ref" href="real_1.html#D5">REAL_1:def 5</a></i>;<br/>
<a NAME="E9:60"/><i><font color="Green">E47</font></i>: 
<font color="Maroon">c<sub>4</sub></font> <a href="int_1.html#R2">divides</a>  <a href="rat_1.html#K2">numerator</a> <font color="Maroon">c<sub>1</sub></font>
 
<b>by </b><i><a class="ref" href="int_2.html#T31">INT_2:31</a></i>;<br/>
<a NAME="E10:60"/>
<span class="p1">(<span class="default"><a href="rat_1.html#K2">numerator</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> <a href="int_2.html#K3">gcd</a> <span class="p1">(<span class="default"><a href="rat_1.html#K1">denominator</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> <a href="int_1.html#R2">divides</a>  <a href="rat_1.html#K1">denominator</a> <font color="Maroon">c<sub>1</sub></font>
 
<b>by </b><i><a class="ref" href="int_2.html#T32">INT_2:32</a></i>;<br/>
<a NAME="E11:60"/><b>then </b><i><font color="Green">E48</font></i>: 
<font color="Maroon">c<sub>4</sub></font> <a href="nat_1.html#R1">divides</a>  <a href="rat_1.html#K1">denominator</a> <font color="Maroon">c<sub>1</sub></font>
 
<b>by </b><i><a class="txt" href="wsierp_1.html#E12"><i><font color="Green">Lemma7</font></i></a></i>;<br/>
<b>consider </b><font color="Maroon">c<sub>5</sub></font> being   <a href="int_1.html#NM1">Integer</a><b> such that </b><br/><a NAME="E13:60"/><i><font color="Green">E49</font></i>: 
 <a href="rat_1.html#K2">numerator</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>4</sub></font> <a href="xcmplx_0.html#K3">*</a> <font color="Maroon">c<sub>5</sub></font>
 <b>by </b><i><a class="txt" href="wsierp_1.html#E9:60"><i><font color="Green">E47</font></i></a>, <a class="ref" href="int_1.html#D9">INT_1:def 9</a></i>;<br/>
<b>consider </b><font color="Maroon">c<sub>6</sub></font> being   <a href="nat_1.html#NM1">Nat</a><b> such that </b><br/><a NAME="E15:60"/><i><font color="Green">E50</font></i>: 
 <a href="rat_1.html#K1">denominator</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>4</sub></font> <a href="nat_1.html#K2">*</a> <font color="Maroon">c<sub>6</sub></font>
 <b>by </b><i><a class="txt" href="wsierp_1.html#E11:60"><i><font color="Green">E48</font></i></a>, <a class="ref" href="nat_1.html#D3">NAT_1:def 3</a></i>;<br/>
<b>thus </b><a NAME="E16:60"/>
contradiction
 <b>by </b><i><a class="txt" href="wsierp_1.html#E8:60"><i><font color="Green">E46</font></i></a>, <a class="txt" href="wsierp_1.html#E13:60"><i><font color="Green">E49</font></i></a>, <a class="txt" href="wsierp_1.html#E15:60"><i><font color="Green">E50</font></i></a>, <a class="ref" href="rat_1.html#T62">RAT_1:62</a></i>;<br/>


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