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<b>let </b><font color="Maroon">i</font> be  <a href="ordinal1.html#V7">natural</a>  <a href="ordinal1.html#NM1" target="_self">number</a> , <font color="Maroon">j</font> be  <a href="ordinal1.html#V7">natural</a>  <a href="ordinal1.html#NM1" target="_self">number</a> ;<br/>

<b>assume </b><a NAME="E1:31"/>
<font color="Maroon">i</font> <a href="xxreal_0.html#NR2" target="_self">&gt;=</a> <font color="Maroon">j</font>
 ;<br/>

<a NAME="E2:31"/><b>then </b>
 ex <font color="Olive">m</font> being  <a href="nat_1.html#NM1">Nat</a> st <font color="Maroon">i</font> <a href="hidden.html#R1">=</a> <font color="Maroon">j</font> <a href="xcmplx_0.html#K2">+</a> <font color="Olive">m</font>
 
<b>by </b><i><a class="ref" href="nat_1.html#T28">NAT_1:28</a></i>;<br/>
<b>hence </b><a NAME="E3:31"/>
<span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="binarith.html#K3" target="_self">-'</a> <font color="Maroon">j</font></span>)</span> <a href="xcmplx_0.html#K2">+</a> <font color="Maroon">j</font> <a href="hidden.html#R1">=</a> <font color="Maroon">i</font>
 <b>by </b><i/>;<br/>


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