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<b>set </b><font color="Maroon">c<sub>3</sub></font> =  <a href="card_3.html#K4">product</a> <font color="Maroon">c<sub>2</sub></font>;<br/>
<div><i><font color="Green">E3</font></i>: <a class="txt" onclick="hs2(this)" href="javascript:()" title="7_1_1_1"><b>now </b></a><div class="add"><b>let </b><font color="Maroon">c<sub>4</sub></font>, <font color="Maroon">c<sub>5</sub></font> be   <a href="funct_1.html#NM1">Function</a>;<br/><b>assume </b><a NAME="E1:7_1_1_1"/>
( <font color="Maroon">c<sub>4</sub></font> <a href="hidden.html#R2">in</a>  <a href="card_3.html#K4">product</a> <font color="Maroon">c<sub>2</sub></font> &amp; <font color="Maroon">c<sub>5</sub></font> <a href="hidden.html#R2">in</a>  <a href="card_3.html#K4">product</a> <font color="Maroon">c<sub>2</sub></font> )
 ;<br/><a NAME="E2:7_1_1_1"/><b>then </b>
(  <a href="relat_1.html#K1">dom</a> <font color="Maroon">c<sub>4</sub></font> <a href="hidden.html#R1">=</a>  <a href="relat_1.html#K1">dom</a> <font color="Maroon">c<sub>2</sub></font> &amp;  <a href="relat_1.html#K1">dom</a> <font color="Maroon">c<sub>5</sub></font> <a href="hidden.html#R1">=</a>  <a href="relat_1.html#K1">dom</a> <font color="Maroon">c<sub>2</sub></font> )
 <b>by </b><i><a class="ref" href="card_3.html#T18">CARD_3:18</a></i>;<br/><b>hence </b><a NAME="E3:7_1_1_1"/>
 <a href="relat_1.html#K1">dom</a> <font color="Maroon">c<sub>4</sub></font> <a href="hidden.html#R1">=</a>  <a href="relat_1.html#K1">dom</a> <font color="Maroon">c<sub>5</sub></font>
 ;<br/></div><b>end;</b></div>
<b>thus </b><a NAME="E2:7_1_1"/>
(  <a href="card_3.html#K4">product</a> <font color="Maroon">c<sub>2</sub></font> is <a href="pralg_2.html#V1" target="_self">with_common_domain</a> &amp;  <a href="card_3.html#K4">product</a> <font color="Maroon">c<sub>2</sub></font> is <a href="fraenkel.html#V1">functional</a> &amp; not  <a href="card_3.html#K4">product</a> <font color="Maroon">c<sub>2</sub></font> is <a href="xboole_0.html#V1">empty</a> )
 <b>by </b><i><a class="txt" href="pralg_2.html#E1:7_1_1"><i><font color="Green">E3</font></i></a>, <a class="ref" href="pralg_2.html#D1" target="_self">Def1</a></i>;<br/>


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