This may help:
- use hMatrix to find the eigenvalues of the adjacency matrix

Then by the following theorems:

"An upper bound on the chromatic number in terms of eigenvalues was
discovered by Wilf(1967).

Chromatic Number(G) <= 1 + lambda_1(G)

Hoffman (1977) discovered a lower bound on the chromatic number in terms of
the smallest and largest eigenvalue.

Chromatic Number(G)  >= 1 - (lambda_1/lambda_n) for n>=2."

From "The Mutually Beneficial Relationship of Graphs and Matrices", Richard
A. Brualdi,CBMS Series,Number 115, 2011.



On Fri, Jul 13, 2012 at 1:43 PM, Alec Story <avs38@corn...> wrote:

> I have a problem where I need to find the smallest k-coloring for a graph
> that represents conflicts between objects.  Is there a Haskell library that
> will do this for me?  I'm not particularly concerned about speed, and it's
> unlikely that I'll generate really bad edge cases, but I'd prefer to do
> something other than write the really bad try-every-case algorithm.
>
> --
> Alec Story
> Cornell University
> Biological Sciences, Computer Science 2012
>
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> http://www.haskell.org/mailman/listinfo/beginners
>
>


--
--
Regards,
KC