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Topic: Note to Quasi from Bill
Replies: 1   Last Post: Jun 21, 2013 5:39 AM

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b92057@yahoo.com

Posts: 1,187
Registered: 4/18/05
Note to Quasi from Bill
Posted: Jun 20, 2013 7:38 PM
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I don't seem to be able to post a reply or contact google for help. So I am answering your comments in a separate post.
My comments are indented.

What are MA vertices?

mutually adjacent vertices.

Then connect vertex 5 to each of the first four.

No.

Any non-complete graph with 5 vertices is 4-colorable.
Not if the graph is non-planar.

If there are no forceable sets of four vertices the graph must be 4 colorable.

Except that I've already shown you a counterexample.

Is your example planar?
bill









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