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Theorem 2 (Kuratowski) says that a graph is nonplanar if and only if it contains a subgraph homeomorphic to <math> K_{3,3} </math> or <math> K_{5} </math>.<br>
 
Theorem 2 (Kuratowski) says that a graph is nonplanar if and only if it contains a subgraph homeomorphic to <math> K_{3,3} </math> or <math> K_{5} </math>.<br>
Looking at the given graph, it is obvious to see that it contains a subgraph homeomorphic to <math> K_{5} </math>.  Therefore, the given graph is nonplanar.<br><br>
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Looking at the given graph, it is obvious to see that it contains a subgraph homeomorphic to <math> K_{5} </math> (a, c, d, f, and h form the pentagon, and everything inside of the pentagon forms the rest of <math> K_{5}</math>.  Therefore, the given graph is nonplanar.<br><br>
 
--[[User:Aoser|Aoser]] 16:59, 5 December 2008 (UTC)
 
--[[User:Aoser|Aoser]] 16:59, 5 December 2008 (UTC)

Latest revision as of 13:02, 5 December 2008

Theorem 2 (Kuratowski) says that a graph is nonplanar if and only if it contains a subgraph homeomorphic to $ K_{3,3} $ or $ K_{5} $.
Looking at the given graph, it is obvious to see that it contains a subgraph homeomorphic to $ K_{5} $ (a, c, d, f, and h form the pentagon, and everything inside of the pentagon forms the rest of $ K_{5} $. Therefore, the given graph is nonplanar.

--Aoser 16:59, 5 December 2008 (UTC)

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