Re: maximal 3-colorable subset




johank wrote:
Hi all,

I am looking for references on the following problem:

given a graph G=(V,E),

and an integer k,

is there a subset V' of V of size k that is 3-colorable?

That is, a optimisation variant of graph coloring that fixes the number
of colors, and optimises the number of vertices that can be colored,
rather than optimising the number of colors used to color everything.

What you have given is not an optimization problem; an optimization
problem would return a "partial" coloring
c:A -> {1,2,...,k} with A (a subset of the vertices) of maximum size.

Although this seems a rather 'natural' problem to me I have
difficulties finding references that address such problems. Any
pointers would me most appreciated.

If you could solve this problem in polynomial time, then you can solve
3-colorability in polynomial time by sending n with a graph G to it.

However, there are some results in the literature involving "defective
colorings"; a k-coloring is d-defective if you can color the vertices
of a graph G such that the subgraphs induced by every color have degree
<= k; that is, every vertex is adjacent to at most k vertices of the
same color. You might be interested in (k,1) colorings. (I don't have
access to MathSciNet at the moment, so I can't make any suggestions.)

--- Christopher Heckman

.



Relevant Pages

  • Re: weighted 2-regular graph local optimization
    ... There is a weighted complete graph, ... to weight (I'm looking into smallest possible aggregated weight of full ... The only operation that is allowed is swapping of neighbor nodes e.g. ... Environment in which this optimization can occur is limited by ...
    (sci.math)
  • weighted 2-regular graph local optimization
    ... There is a weighted complete graph, ... to weight (I'm looking into smallest possible aggregated weight of full ... The only operation that is allowed is swapping of neighbor nodes e.g. ... Environment in which this optimization can occur is limited by ...
    (sci.math)
  • Re: The Lazy Persons Guide to Proving the Four Color Theorem
    ... In fact, the 4CT is false if there is a graph G with Chi> 4, ... For every possible 4-coloring of, there can be no proper ... rest of G, or equivalently, if C is a coloring of G, then Chas four ... You assumed we can recolor just v_a; ...
    (sci.math)
  • Re: Four Color Theorem
    ... My proof is based on the assumption that the following graph is not 4-chroma. ... Without the internal chord ... All you have done is made one coloring fail to work; ... that no minimal counterexample of the 4CT contains K4. ...
    (sci.math)
  • Re: Four Color Theorem
    ... My proof is based on the assumption that the following graph is not 4-chroma. ... Without the internal chord ... All you have done is made one coloring fail to work; ... that no minimal counterexample of the 4CT contains K4. ...
    (sci.math)