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<b>let </b><font color="Maroon">c<sub>1</sub></font> be  <a href="rat_1.html#V1">rational</a>  <a href="ordinal1.html#NM1" target="_self">number</a> ;<br/><b>let </b><font color="Maroon">c<sub>2</sub></font> be  <a href="xreal_0.html#V1">real</a> <a href="rat_1.html#V1">irrational</a>  <a href="ordinal1.html#NM1" target="_self">number</a> ;<br/>



<a NAME="E1:42"/>
<font color="Maroon">c<sub>2</sub></font> <a href="xcmplx_0.html#K2">+</a> <span class="p1">(<span class="default"><a href="xcmplx_0.html#K4">-</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> is <a href="rat_1.html#V1">irrational</a>
 
<b>by </b><i><a class="ref" href="borsuk_5.html#T38" target="_self">Th38</a></i>;<br/>
<b>hence </b><a NAME="E2:42"/>
<font color="Maroon">c<sub>2</sub></font> <a href="xcmplx_0.html#K6">-</a> <font color="Maroon">c<sub>1</sub></font> is <a href="rat_1.html#V1">irrational</a>
 ;<br/>


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