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<b>let </b><font color="Maroon" title="c1">p1</font>, <font color="Maroon" title="c2">p2</font>, <font color="Maroon" title="c3">p3</font>, <font color="Maroon" title="c4">p4</font> be   <a href="pre_topc.html#NM2" title="PRE_TOPC:NM.2">Point</a> of <span class="p1">(<span class="default"><a href="euclid.html#K15" title="EUCLID:func.15">TOP-REAL</a> 3</span>)</span>;<br/>







<span class="p1">(<span class="default"><font color="Maroon" title="c1">p1</font> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <font color="Maroon" title="c2">p2</font></span>)</span> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <span class="p1">(<span class="default"><font color="Maroon" title="c3">p3</font> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <font color="Maroon" title="c4">p4</font></span>)</span> = 
<span class="p1">(<span class="default"><font color="Maroon" title="c1">p1</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <span class="p2">(<span class="default"><font color="Maroon" title="c3">p3</font> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <font color="Maroon" title="c4">p4</font></span>)</span></span>)</span> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <span class="p1">(<span class="default"><font color="Maroon" title="c2">p2</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <span class="p2">(<span class="default"><font color="Maroon" title="c3">p3</font> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <font color="Maroon" title="c4">p4</font></span>)</span></span>)</span>
<b>by </b><i><a class="ref" href="euclid_5.html#T24" target="_self" title="EUCLID_5:th.24">Th24</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c1">p1</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c3">p3</font></span>)</span> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <span class="p2">(<span class="default"><font color="Maroon" title="c1">p1</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c4">p4</font></span>)</span></span>)</span> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <span class="p1">(<span class="default"><font color="Maroon" title="c2">p2</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <span class="p2">(<span class="default"><font color="Maroon" title="c3">p3</font> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <font color="Maroon" title="c4">p4</font></span>)</span></span>)</span>
<b>by </b><i><a class="ref" href="euclid_5.html#T23" target="_self" title="EUCLID_5:th.23">Th23</a></i>
<br/>.= 
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c1">p1</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c3">p3</font></span>)</span> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <span class="p2">(<span class="default"><font color="Maroon" title="c1">p1</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c4">p4</font></span>)</span></span>)</span> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c2">p2</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c3">p3</font></span>)</span> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <span class="p2">(<span class="default"><font color="Maroon" title="c2">p2</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c4">p4</font></span>)</span></span>)</span>
<b>by </b><i><a class="ref" href="euclid_5.html#T23" target="_self" title="EUCLID_5:th.23">Th23</a></i>
;<br/>
<b>hence </b><a NAME="E2:27"/>
<span class="p1">(<span class="default"><font color="Maroon" title="c1">p1</font> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <font color="Maroon" title="c2">p2</font></span>)</span> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <span class="p1">(<span class="default"><font color="Maroon" title="c3">p3</font> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <font color="Maroon" title="c4">p4</font></span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon" title="c1">p1</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c3">p3</font></span>)</span> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <span class="p3">(<span class="default"><font color="Maroon" title="c1">p1</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c4">p4</font></span>)</span></span>)</span> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <span class="p2">(<span class="default"><font color="Maroon" title="c2">p2</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c3">p3</font></span>)</span></span>)</span> <a href="euclid.html#K17" title="EUCLID:func.17">+</a> <span class="p1">(<span class="default"><font color="Maroon" title="c2">p2</font> <a href="euclid_5.html#K5" title="EUCLID_5:func.5">&lt;X&gt;</a> <font color="Maroon" title="c4">p4</font></span>)</span>
 <b>by </b><i><a class="ref" href="euclid.html#T30" title="EUCLID:th.30">EUCLID:30</a></i>;<br/>


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