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

<a NAME="E1:22_1_1"/>
 <a href="card_3.html#K3">Union</a> <font color="Maroon">A1</font> is   <a href="subset_1.html#NM2">Subset</a> of <font color="Maroon">X</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="22_1_1_1"><b>proof </b></a><div class="add">

<a NAME="E1:22_1_1_1"/>
 <a href="card_3.html#K3">Union</a> <font color="Maroon">A1</font> <a href="hidden.html#R1">=</a>  <a href="tarski.html#K3">union</a> <span class="p1">(<span class="default"><a href="relat_1.html#K2">rng</a> <font color="Maroon">A1</font></span>)</span>
 
<b>by </b><i><a class="ref" href="card_3.html#D4">CARD_3:def 4</a></i>;<br/>
<b>hence </b><a NAME="E2:22_1_1_1"/>
 <a href="card_3.html#K3">Union</a> <font color="Maroon">A1</font> is   <a href="subset_1.html#NM2">Subset</a> of <font color="Maroon">X</font>
 <b>by </b><i/>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E2:22_1_1"/>
 <a href="card_3.html#K3">Union</a> <font color="Maroon">A1</font> is   <a href="subset_1.html#NM2">Subset</a> of <font color="Maroon">X</font>
 ;<br/>


</div>
