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

<b>let </b><font color="Maroon" title="c1">I</font> be  <a href="group_1.html#V7" title="GROUP_1:attr.7">commutative</a> non <a href="vectsp_1.html#V10" title="VECTSP_1:attr.10">degenerated</a> <a href="vectsp_2.html#V2" title="VECTSP_2:attr.2">domRing-like</a> <a href="funcsdom.html#NM1" title="FUNCSDOM:NM.1">Ring</a>;<br/><b>let </b><font color="Maroon" title="c2">u</font>, <font color="Maroon" title="c3">v</font> be    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="quofield.html#K9" title="QUOFIELD:func.9">Quot.</a> <font color="Maroon" title="c1">I</font>;<br/>



<b>assume </b><a NAME="E1:19"/><i><font color="Green" title="E13">A1</font></i>: 
<font color="Maroon" title="c2">u</font> <a href="subset_1.html#K9" title="SUBSET_1:func.9">/\</a> <font color="Maroon" title="c3">v</font> <a href="hidden.html#NR2" title="HIDDEN:NR.2">&lt;&gt;</a>  <a href="xboole_0.html#K1" title="XBOOLE_0:func.1">{}</a> 
 ; <i><font color="Red">:: according to </font></i><a class="ref" href="xboole_0.html#D7" title="XBOOLE_0:def.7">XBOOLE_0:def 7</a><br/>

<b>consider </b><font color="Maroon" title="c4">x</font> being    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="quofield.html#K1" title="QUOFIELD:func.1">Q.</a> <font color="Maroon" title="c1">I</font><b> such that </b><br/><a NAME="E3:19"/><i><font color="Green" title="E14">A2</font></i>: 
<font color="Maroon" title="c2">u</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c4">x</font>
 <b>by </b><i><a class="ref" href="quofield.html#D5" target="_self" title="QUOFIELD:def.5">Def5</a></i>;<br/>
<b>consider </b><font color="Maroon" title="c5">y</font> being    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="quofield.html#K1" title="QUOFIELD:func.1">Q.</a> <font color="Maroon" title="c1">I</font><b> such that </b><br/><a NAME="E5:19"/><i><font color="Green" title="E15">A3</font></i>: 
<font color="Maroon" title="c3">v</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c5">y</font>
 <b>by </b><i><a class="ref" href="quofield.html#D5" target="_self" title="QUOFIELD:def.5">Def5</a></i>;<br/>
<a NAME="E6:19"/>
<font color="Maroon" title="c2">u</font> <a href="xboole_0.html#NR5" title="XBOOLE_0:NR.5">meets</a> <font color="Maroon" title="c3">v</font>
 
<b>by </b><i><a class="txt" href="quofield.html#E1:19"><i><font color="Green" title="E13">A1</font></i></a>, <a class="ref" href="xboole_0.html#D7" title="XBOOLE_0:def.7">XBOOLE_0:def 7</a></i>;<br/>
<b>then consider </b><font color="Maroon" title="c6">w</font> being    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> <b> such that </b><br/><a NAME="E8:19"/><i><font color="Green" title="E16">A4</font></i>: 
( <font color="Maroon" title="c6">w</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">u</font> &amp; <font color="Maroon" title="c6">w</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c3">v</font> )
 <b>by </b><i><a class="ref" href="xboole_0.html#T3" title="XBOOLE_0:th.3">XBOOLE_0:3</a></i>;<br/>
<b>reconsider </b><font color="Maroon" title="c7">w</font> = <font color="Maroon" title="c6">w</font> as    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="quofield.html#K1" title="QUOFIELD:func.1">Q.</a> <font color="Maroon" title="c1">I</font> <b>by </b><i><a class="txt" href="quofield.html#E8:19"><i><font color="Green" title="E16">A4</font></i></a></i>;<br/>
<a NAME="E10:19"/><i><font color="Green" title="E17">A5</font></i>: 
<span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span>
 
<b>by </b><i><a class="txt" href="quofield.html#E3:19"><i><font color="Green" title="E14">A2</font></i></a>, <a class="txt" href="quofield.html#E8:19"><i><font color="Green" title="E16">A4</font></i></a>, <a class="ref" href="quofield.html#D4" target="_self" title="QUOFIELD:def.4">Def4</a></i>;<br/>
<a NAME="E11:19"/><i><font color="Green" title="E18">A6</font></i>: 
<span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span>
 
<b>by </b><i><a class="txt" href="quofield.html#E5:19"><i><font color="Green" title="E15">A3</font></i></a>, <a class="txt" href="quofield.html#E8:19"><i><font color="Green" title="E16">A4</font></i></a>, <a class="ref" href="quofield.html#D4" target="_self" title="QUOFIELD:def.4">Def4</a></i>;<br/>
<a NAME="E12:19"/><i><font color="Green" title="E19">A7</font></i>: 
for <font color="Olive" title="b1">z</font> being   <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="quofield.html#K1" title="QUOFIELD:func.1">Q.</a> <font color="Maroon" title="c1">I</font>  st <font color="Olive" title="b1">z</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c4">x</font> holds <br/><font color="Olive" title="b1">z</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c5">y</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="19_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon" title="c8">z</font> be    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="quofield.html#K1" title="QUOFIELD:func.1">Q.</a> <font color="Maroon" title="c1">I</font>;<br/>

<b>assume </b><a NAME="E1:19_1"/>
<font color="Maroon" title="c8">z</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c4">x</font>
 ;<br/>

<a NAME="E2:19_1"/><b>then </b><i><font color="Green" title="E20">A8</font></i>: 
<span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span>
 
<b>by </b><i><a class="txt" href="quofield.html#E3:19"><i><font color="Green" title="E14">A2</font></i></a>, <a class="txt" href="quofield.html#E8:19"><i><font color="Green" title="E16">A4</font></i></a>, <a class="ref" href="quofield.html#T8" target="_self" title="QUOFIELD:th.8">Th8</a></i>;<br/>
<a NAME="E3:19_1"/><b>then </b><i><font color="Green" title="E21">A9</font></i>: 
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="gcd_1.html#R2" title="GCD_1:pred.2">divides</a> <span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span>
 
<b>by </b><i><a class="ref" href="gcd_1.html#D1" title="GCD_1:def.1">GCD_1:def 1</a></i>;<br/>
<a NAME="E4:19_1"/><b>then </b><i><font color="Green" title="E22">A10</font></i>: 
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="gcd_1.html#R2" title="GCD_1:pred.2">divides</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
 
<b>by </b><i><a class="ref" href="gcd_1.html#T7" title="GCD_1:th.7">GCD_1:7</a></i>;<br/>
<a NAME="E5:19_1"/>
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="gcd_1.html#R2" title="GCD_1:pred.2">divides</a> <font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> 
 
;<br/>
<a NAME="E6:19_1"/><b>then </b><i><font color="Green" title="E23">A11</font></i>: 
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="gcd_1.html#R2" title="GCD_1:pred.2">divides</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
 
<b>by </b><i><a class="ref" href="gcd_1.html#T7" title="GCD_1:th.7">GCD_1:7</a></i>;<br/>
<a NAME="E7:19_1"/><i><font color="Green" title="E24">A12</font></i>: 
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="hidden.html#NR2" title="HIDDEN:NR.2">&lt;&gt;</a>  <a href="rlvect_1.html#K1" title="RLVECT_1:func.1">0.</a> <font color="Maroon" title="c1">I</font>
 
<b>by </b><i><a class="ref" href="quofield.html#T2" target="_self" title="QUOFIELD:th.2">Th2</a></i>;<br/>
<b>then </b><span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> = 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p3">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E2:19_1"><i><font color="Green" title="E20">A8</font></i></a>, <a class="txt" href="quofield.html#E3:19_1"><i><font color="Green" title="E21">A9</font></i></a>, <a class="ref" href="gcd_1.html#D4" title="GCD_1:def.4">GCD_1:def 4</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p3">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span></span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E3:19_1"><i><font color="Green" title="E21">A9</font></i></a>, <a class="txt" href="quofield.html#E4:19_1"><i><font color="Green" title="E22">A10</font></i></a>, <a class="txt" href="quofield.html#E7:19_1"><i><font color="Green" title="E24">A12</font></i></a>, <a class="ref" href="gcd_1.html#T11" title="GCD_1:th.11">GCD_1:11</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p3">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span></span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E11:19"><i><font color="Green" title="E18">A6</font></i></a>, <a class="ref" href="group_1.html#D4" title="GROUP_1:def.4">GROUP_1:def 4</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p3">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span></span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
<b>by </b><i><a class="ref" href="group_1.html#D4" title="GROUP_1:def.4">GROUP_1:def 4</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span></span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E6:19_1"><i><font color="Green" title="E23">A11</font></i></a>, <a class="txt" href="quofield.html#E7:19_1"><i><font color="Green" title="E24">A12</font></i></a>, <a class="ref" href="gcd_1.html#T11" title="GCD_1:th.11">GCD_1:11</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><a href="group_1.html#K2" title="GROUP_1:func.2">1.</a> <font color="Maroon" title="c1">I</font></span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E7:19_1"><i><font color="Green" title="E24">A12</font></i></a>, <a class="ref" href="gcd_1.html#T9" title="GCD_1:th.9">GCD_1:9</a></i>
<br/>.= 
<span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c5">y</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span>
<b>by </b><i><a class="ref" href="vectsp_1.html#D13" title="VECTSP_1:def.13">VECTSP_1:def 13</a></i>
;<br/>
<b>hence </b><a NAME="E9:19_1"/>
<font color="Maroon" title="c8">z</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c5">y</font>
 <b>by </b><i><a class="ref" href="quofield.html#D4" target="_self" title="QUOFIELD:def.4">Def4</a></i>;<br/>


</div><b>end;</b></div>
<a NAME="E13:19"/>
for <font color="Olive" title="b1">z</font> being   <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="quofield.html#K1" title="QUOFIELD:func.1">Q.</a> <font color="Maroon" title="c1">I</font>  st <font color="Olive" title="b1">z</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c5">y</font> holds <br/><font color="Olive" title="b1">z</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c4">x</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="19_2"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon" title="c8">z</font> be    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="quofield.html#K1" title="QUOFIELD:func.1">Q.</a> <font color="Maroon" title="c1">I</font>;<br/>

<b>assume </b><a NAME="E1:19_2"/>
<font color="Maroon" title="c8">z</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c5">y</font>
 ;<br/>

<a NAME="E2:19_2"/><b>then </b><i><font color="Green" title="E20">A13</font></i>: 
<span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span>
 
<b>by </b><i><a class="txt" href="quofield.html#E5:19"><i><font color="Green" title="E15">A3</font></i></a>, <a class="txt" href="quofield.html#E8:19"><i><font color="Green" title="E16">A4</font></i></a>, <a class="ref" href="quofield.html#T8" target="_self" title="QUOFIELD:th.8">Th8</a></i>;<br/>
<a NAME="E3:19_2"/><b>then </b><i><font color="Green" title="E21">A14</font></i>: 
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="gcd_1.html#R2" title="GCD_1:pred.2">divides</a> <span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span>
 
<b>by </b><i><a class="ref" href="gcd_1.html#D1" title="GCD_1:def.1">GCD_1:def 1</a></i>;<br/>
<a NAME="E4:19_2"/><b>then </b><i><font color="Green" title="E22">A15</font></i>: 
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="gcd_1.html#R2" title="GCD_1:pred.2">divides</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
 
<b>by </b><i><a class="ref" href="gcd_1.html#T7" title="GCD_1:th.7">GCD_1:7</a></i>;<br/>
<a NAME="E5:19_2"/>
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="gcd_1.html#R2" title="GCD_1:pred.2">divides</a> <font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> 
 
;<br/>
<a NAME="E6:19_2"/><b>then </b><i><font color="Green" title="E23">A16</font></i>: 
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="gcd_1.html#R2" title="GCD_1:pred.2">divides</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
 
<b>by </b><i><a class="ref" href="gcd_1.html#T7" title="GCD_1:th.7">GCD_1:7</a></i>;<br/>
<a NAME="E7:19_2"/><i><font color="Green" title="E24">A17</font></i>: 
<font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a>  <a href="hidden.html#NR2" title="HIDDEN:NR.2">&lt;&gt;</a>  <a href="rlvect_1.html#K1" title="RLVECT_1:func.1">0.</a> <font color="Maroon" title="c1">I</font>
 
<b>by </b><i><a class="ref" href="quofield.html#T2" target="_self" title="QUOFIELD:th.2">Th2</a></i>;<br/>
<b>then </b><span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> = 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p3">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E2:19_2"><i><font color="Green" title="E20">A13</font></i></a>, <a class="txt" href="quofield.html#E3:19_2"><i><font color="Green" title="E21">A14</font></i></a>, <a class="ref" href="gcd_1.html#D4" title="GCD_1:def.4">GCD_1:def 4</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p3">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span></span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E3:19_2"><i><font color="Green" title="E21">A14</font></i></a>, <a class="txt" href="quofield.html#E4:19_2"><i><font color="Green" title="E22">A15</font></i></a>, <a class="txt" href="quofield.html#E7:19_2"><i><font color="Green" title="E24">A17</font></i></a>, <a class="ref" href="gcd_1.html#T11" title="GCD_1:th.11">GCD_1:11</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p3">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span></span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E10:19"><i><font color="Green" title="E17">A5</font></i></a>, <a class="ref" href="group_1.html#D4" title="GROUP_1:def.4">GROUP_1:def 4</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p3">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span></span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p1">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span>
<b>by </b><i><a class="ref" href="group_1.html#D4" title="GROUP_1:def.4">GROUP_1:def 4</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="gcd_1.html#K1" title="GCD_1:func.1">/</a> <span class="p2">(<span class="default"><font color="Maroon" title="c7">w</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span></span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E6:19_2"><i><font color="Green" title="E23">A16</font></i></a>, <a class="txt" href="quofield.html#E7:19_2"><i><font color="Green" title="E24">A17</font></i></a>, <a class="ref" href="gcd_1.html#T11" title="GCD_1:th.11">GCD_1:11</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p2">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span></span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><a href="group_1.html#K2" title="GROUP_1:func.2">1.</a> <font color="Maroon" title="c1">I</font></span>)</span>
<b>by </b><i><a class="txt" href="quofield.html#E7:19_2"><i><font color="Green" title="E24">A17</font></i></a>, <a class="ref" href="gcd_1.html#T9" title="GCD_1:th.9">GCD_1:9</a></i>
<br/>.= 
<span class="p1">(<span class="default"><font color="Maroon" title="c8">z</font> <a href="quofield.html#K3" title="QUOFIELD:func.3">`2</a> </span>)</span> <a href="group_1.html#K10" title="GROUP_1:func.10">*</a> <span class="p1">(<span class="default"><font color="Maroon" title="c4">x</font> <a href="quofield.html#K2" title="QUOFIELD:func.2">`1</a> </span>)</span>
<b>by </b><i><a class="ref" href="vectsp_1.html#D13" title="VECTSP_1:def.13">VECTSP_1:def 13</a></i>
;<br/>
<b>hence </b><a NAME="E9:19_2"/>
<font color="Maroon" title="c8">z</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="quofield.html#K8" title="QUOFIELD:func.8">QClass.</a> <font color="Maroon" title="c4">x</font>
 <b>by </b><i><a class="ref" href="quofield.html#D4" target="_self" title="QUOFIELD:def.4">Def4</a></i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E14:19"/>
<font color="Maroon" title="c2">u</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c3">v</font>
 <b>by </b><i><a class="txt" href="quofield.html#E3:19"><i><font color="Green" title="E14">A2</font></i></a>, <a class="txt" href="quofield.html#E5:19"><i><font color="Green" title="E15">A3</font></i></a>, <a class="txt" href="quofield.html#E12:19"><i><font color="Green" title="E19">A7</font></i></a>, <a class="ref" href="subset_1.html#T8" title="SUBSET_1:th.8">SUBSET_1:8</a></i>;<br/>


</div>
