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The graph coloring game is a mathematical game related to graph theory. Coloring game problems arose as game-theoretic versions of well-known graph coloring problems. In a coloring game, two players use a given set of colors to construct a coloring of a graph, following specific rules depending on the game we consider.
With four colors, it can be colored in 24 + 4 × 12 = 72 ways: using all four colors, there are 4! = 24 valid colorings (every assignment of four colors to any 4-vertex graph is a proper coloring); and for every choice of three of the four colors, there are 12 valid 3-colorings. So, for the graph in the example, a table of the number of valid ...
The above shows that in terms of the number of vertices, the upper bound () is the best possible in general. In fact, a rainbow coloring using colors can be constructed by coloring the edges of a spanning tree of in distinct colors. The remaining uncolored edges are colored arbitrarily, without introducing new colors.
The graphs that are both perfect graphs and -perfect graphs are exactly the chordal graphs. On even-hole-free graphs more generally, the degeneracy ordering approximates the optimal coloring to within at most twice the optimal number of colors; that is, its approximation ratio is 2. [20]
For a graph G, let χ(G) denote the chromatic number and Δ(G) the maximum degree of G.The list coloring number ch(G) satisfies the following properties.. ch(G) ≥ χ(G).A k-list-colorable graph must in particular have a list coloring when every vertex is assigned the same list of k colors, which corresponds to a usual k-coloring.
Eight asymmetric graphs, each given a distinguishing coloring with only one color (red) A graph has distinguishing number one if and only if it is asymmetric. [3] For instance, the Frucht graph has a distinguishing coloring with only one color. In a complete graph, the only distinguishing colorings assign a different color to each vertex. For ...
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Below: A 5:2 coloring of the same graph. A b-fold coloring of a graph G is an assignment of sets of size b to vertices of a graph such that adjacent vertices receive disjoint sets. An a:b-coloring is a b-fold coloring out of a available colors. Equivalently, it can be defined as a homomorphism to the Kneser graph KG a,b.