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<b>let </b><font color="Maroon">X</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">Y</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">Z</font> be    <a href="hidden.html#M1">set</a> ;<br/>





<a NAME="E1:43"/><i><font color="Green">E40</font></i>: 
(  <a href="tarski.html#K3">union</a> <span class="p1">(<span class="default"><span class="p2"><a href="tarski.html#K2">{</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="tarski.html#K2">}</a></span> <a href="xboole_0.html#K2">\/</a> <span class="p2"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">Z</font></span><a href="tarski.html#K1">}</a></span></span>)</span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><a href="tarski.html#K3">union</a> <span class="p2"><a href="tarski.html#K2">{</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="tarski.html#K2">}</a></span></span>)</span> <a href="xboole_0.html#K2">\/</a> <span class="p1">(<span class="default"><a href="tarski.html#K3">union</a> <span class="p2"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">Z</font></span><a href="tarski.html#K1">}</a></span></span>)</span> &amp;  <a href="tarski.html#K3">union</a> <span class="p1"><a href="tarski.html#K2">{</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="tarski.html#K2">}</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">X</font> <a href="xboole_0.html#K2">\/</a> <font color="Maroon">Y</font> &amp;  <a href="tarski.html#K3">union</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">Z</font></span><a href="tarski.html#K1">}</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">Z</font> )
 
<b>by </b><i><a class="ref" href="zfmisc_1.html#T31">ZFMISC_1:31</a>, <a class="ref" href="zfmisc_1.html#T93">ZFMISC_1:93</a>, <a class="ref" href="zfmisc_1.html#T96">ZFMISC_1:96</a></i>;<br/>
<a NAME="E2:43"/><i><font color="Green">E41</font></i>: 
(  <a href="setfam_1.html#K1">meet</a> <span class="p1">(<span class="default"><span class="p2"><a href="tarski.html#K2">{</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="tarski.html#K2">}</a></span> <a href="xboole_0.html#K2">\/</a> <span class="p2"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">Z</font></span><a href="tarski.html#K1">}</a></span></span>)</span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K1">meet</a> <span class="p2"><a href="tarski.html#K2">{</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="tarski.html#K2">}</a></span></span>)</span> <a href="xboole_0.html#K3">/\</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K1">meet</a> <span class="p2"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">Z</font></span><a href="tarski.html#K1">}</a></span></span>)</span> &amp;  <a href="setfam_1.html#K1">meet</a> <span class="p1"><a href="tarski.html#K2">{</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="tarski.html#K2">}</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">X</font> <a href="xboole_0.html#K3">/\</a> <font color="Maroon">Y</font> &amp;  <a href="setfam_1.html#K1">meet</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">Z</font></span><a href="tarski.html#K1">}</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">Z</font> )
 
<b>by </b><i><a class="ref" href="setfam_1.html#T10">SETFAM_1:10</a>, <a class="ref" href="setfam_1.html#T11">SETFAM_1:11</a>, <a class="ref" href="setfam_1.html#T12">SETFAM_1:12</a></i>;<br/>
<a NAME="E3:43"/><i><font color="Green">E42</font></i>: 
<span class="p1"><a href="tarski.html#K2">{</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="tarski.html#K2">}</a></span> <a href="xboole_0.html#K2">\/</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">Z</font></span><a href="tarski.html#K1">}</a></span> <a href="hidden.html#R1">=</a> <span class="p1"><a href="enumset1.html#K1">{</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font>,<font color="Maroon">Z</font></span><a href="enumset1.html#K1">}</a></span>
 
<b>by </b><i><a class="ref" href="enumset1.html#T43">ENUMSET1:43</a></i>;<br/>
<b>thus </b> <a href="card_3.html#K3">Union</a> <span class="p1"><a href="finseq_1.html#K11">&lt;*</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font>,<font color="Maroon">Z</font></span><a href="finseq_1.html#K11">*&gt;</a></span> = 
 <a href="tarski.html#K3">union</a> <span class="p1">(<span class="default"><a href="relat_1.html#K2">rng</a> <span class="p2"><a href="finseq_1.html#K11">&lt;*</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font>,<font color="Maroon">Z</font></span><a href="finseq_1.html#K11">*&gt;</a></span></span>)</span>
<b>by </b><i><a class="ref" href="card_3.html#D4">CARD_3:def 4</a></i>
<br/>.= 
<span class="p1">(<span class="default"><font color="Maroon">X</font> <a href="xboole_0.html#K2">\/</a> <font color="Maroon">Y</font></span>)</span> <a href="xboole_0.html#K2">\/</a> <font color="Maroon">Z</font>
<b>by </b><i>, , <a class="ref" href="finseq_2.html#T148">FINSEQ_2:148</a></i>
;<br/>

<b>thus </b><a NAME="E5:43"/>
 <a href="funct_6.html#K4" target="_self">meet</a> <span class="p1"><a href="finseq_1.html#K11">&lt;*</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font>,<font color="Maroon">Z</font></span><a href="finseq_1.html#K11">*&gt;</a></span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">X</font> <a href="xboole_0.html#K3">/\</a> <font color="Maroon">Y</font></span>)</span> <a href="xboole_0.html#K3">/\</a> <font color="Maroon">Z</font>
 <b>by </b><i>, , <a class="ref" href="finseq_2.html#T148">FINSEQ_2:148</a></i>;<br/>


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