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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E27">Th21</font></span>: <a NAME="T21"><span class="comment"><font color="firebrick">:: GRAPH_1:21</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">G</font>, <font color="Olive" title="b2">G1</font>, <font color="Olive" title="b3">G2</font>, <font color="Olive" title="b4">G3</font> being   <a href="graph_1.html#NM3" title="GRAPH_1:NM.3">Graph</a>  st <font color="Olive" title="b2">G1</font> <a href="graph_1.html#R4" title="GRAPH_1:pred.4">c=</a> <font color="Olive" title="b4">G3</font> &amp; <font color="Olive" title="b3">G2</font> <a href="graph_1.html#R4" title="GRAPH_1:pred.4">c=</a> <font color="Olive" title="b4">G3</font> &amp; <font color="Olive" title="b1">G</font> <a href="graph_1.html#R1" title="GRAPH_1:pred.1">is_sum_of</a> <font color="Olive" title="b2">G1</font>,<font color="Olive" title="b3">G2</font> holds <br/><font color="Olive" title="b1">G</font> <a href="graph_1.html#R4" title="GRAPH_1:pred.4">c=</a> <font color="Olive" title="b4">G3</font></div></div>
