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

<b>let </b><font color="Maroon">c<sub>1</sub></font>, <font color="Maroon">c<sub>2</sub></font>, <font color="Maroon">c<sub>3</sub></font> be   <a href="nat_1.html#NM1">Nat</a>;<br/>





<b>set </b><font color="Maroon">c<sub>4</sub></font> = <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>;<br/>
<b>set </b><font color="Maroon">c<sub>5</sub></font> = <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span>;<br/>
<b>set </b><font color="Maroon">c<sub>6</sub></font> = <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font>;<br/>
<b>set </b><font color="Maroon">c<sub>7</sub></font> = <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>;<br/>
<a NAME="E1:61"/>
<font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="61_1"><b>proof </b></a><div class="add">

<a NAME="E1:61_1"/><i><font color="Green">E39</font></i>: 
( <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> &amp; <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> &amp; ( for <font color="Olive">b<sub>1</sub></font> being  <a href="nat_1.html#NM1">Nat</a> st <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> &amp; <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> holds <br/><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> ) )
 
<b>by </b><i><a class="ref" href="nat_1.html#D4">NAT_1:def 4</a></i>;<br/>
<a NAME="E2:61_1"/><i><font color="Green">E40</font></i>: 
( <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> &amp; <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> &amp; ( for <font color="Olive">b<sub>1</sub></font> being  <a href="nat_1.html#NM1">Nat</a> st <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> &amp; <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> holds <br/><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> ) )
 
<b>by </b><i><a class="ref" href="nat_1.html#D4">NAT_1:def 4</a></i>;<br/>
<a NAME="E3:61_1"/><i><font color="Green">E41</font></i>: 
( <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font> &amp; <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font> &amp; ( for <font color="Olive">b<sub>1</sub></font> being  <a href="nat_1.html#NM1">Nat</a> st <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> &amp; <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> holds <br/><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> ) )
 
<b>by </b><i><a class="ref" href="nat_1.html#D4">NAT_1:def 4</a></i>;<br/>
<a NAME="E4:61_1"/><i><font color="Green">E42</font></i>: 
( <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> &amp; <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> &amp; ( for <font color="Olive">b<sub>1</sub></font> being  <a href="nat_1.html#NM1">Nat</a> st <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> &amp; <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> holds <br/><span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Olive">b<sub>1</sub></font> ) )
 
<b>by </b><i><a class="ref" href="nat_1.html#D4">NAT_1:def 4</a></i>;<br/>
<a NAME="E5:61_1"/><i><font color="Green">E43</font></i>: 
<font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="nat_1.html#R1">divides</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="61_1_1"><b>proof </b></a><div class="add">

<a NAME="E1:61_1_1"/><i><font color="Green">E44</font></i>: 
<font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#R1">divides</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>
 
<b>by </b><i><a class="txt" href="newton.html#E3:61_1"><i><font color="Green">E41</font></i></a>, <a class="txt" href="newton.html#E4:61_1"><i><font color="Green">E42</font></i></a>, <a class="ref" href="nat_1.html#T51">NAT_1:51</a></i>;<br/>
<a NAME="E2:61_1_1"/>
<font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>
 
<b>by </b><i><a class="txt" href="newton.html#E3:61_1"><i><font color="Green">E41</font></i></a>, <a class="txt" href="newton.html#E4:61_1"><i><font color="Green">E42</font></i></a>, <a class="ref" href="nat_1.html#T51">NAT_1:51</a></i>;<br/>
<a NAME="E3:61_1_1"/><b>then </b>
<font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>
 
<b>by </b><i><a class="txt" href="newton.html#E4:61_1"><i><font color="Green">E42</font></i></a>, <a class="ref" href="nat_1.html#D4">NAT_1:def 4</a></i>;<br/>
<b>hence </b><a NAME="E4:61_1_1"/>
<font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="nat_1.html#R1">divides</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>
 <b>by </b><i><a class="txt" href="newton.html#E1:61_1_1"><i><font color="Green">E44</font></i></a>, <a class="ref" href="nat_1.html#D4">NAT_1:def 4</a></i>;<br/>


</div><b>end;</b></div>
<a NAME="E6:61_1"/>
<span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="61_1_2"><b>proof </b></a><div class="add">

<a NAME="E1:61_1_2"/><i><font color="Green">E44</font></i>: 
<font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span>
 
<b>by </b><i><a class="txt" href="newton.html#E1:61_1"><i><font color="Green">E39</font></i></a>, <a class="txt" href="newton.html#E2:61_1"><i><font color="Green">E40</font></i></a>, <a class="ref" href="nat_1.html#T51">NAT_1:51</a></i>;<br/>
<a NAME="E2:61_1_2"/>
<font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span>
 
<b>by </b><i><a class="txt" href="newton.html#E1:61_1"><i><font color="Green">E39</font></i></a>, <a class="txt" href="newton.html#E2:61_1"><i><font color="Green">E40</font></i></a>, <a class="ref" href="nat_1.html#T51">NAT_1:51</a></i>;<br/>
<a NAME="E3:61_1_2"/><b>then </b>
<font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span>
 
<b>by </b><i><a class="txt" href="newton.html#E2:61_1"><i><font color="Green">E40</font></i></a>, <a class="ref" href="nat_1.html#D4">NAT_1:def 4</a></i>;<br/>
<b>hence </b><a NAME="E4:61_1_2"/>
<span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font> <a href="nat_1.html#R1">divides</a> <font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span>
 <b>by </b><i><a class="txt" href="newton.html#E1:61_1_2"><i><font color="Green">E44</font></i></a>, <a class="ref" href="nat_1.html#D4">NAT_1:def 4</a></i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E7:61_1"/>
<font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>
 <b>by </b><i><a class="txt" href="newton.html#E5:61_1"><i><font color="Green">E43</font></i></a>, <a class="ref" href="nat_1.html#T52">NAT_1:52</a></i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E2:61"/>
<font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="nat_1.html#K6">lcm</a> <font color="Maroon">c<sub>3</sub></font>
 ;<br/>


</div>
