Abstract:
We introduce a new and rich class of graph coloring manifolds via the Hom complex construction of Lovasz. The class comprises examples of Stiefel manifolds, series of spheres and products of spheres, cubical surfaces, as well as examples of Seifert manifolds. Asymptotically, graph coloring manifolds provide examples of highly connected, highly symmetric manifolds.

Abstract:
We explore the application of graph coloring to biological networks, specifically protein-protein interaction (PPI) networks. First, we find that given similar conditions (i.e. number of nodes, number of links, degree distribution and clustering), fewer colors are needed to color disassortative (high degree nodes tend to connect to low degree nodes and vice versa) than assortative networks. Fewer colors create fewer independent sets which in turn imply higher concurrency potential for a network. Since PPI networks tend to be disassortative, we suggest that in addition to functional specificity and stability proposed previously by Maslov and Sneppen (Science 296, 2002), the disassortative nature of PPI networks may promote the ability of cells to perform multiple, crucial and functionally diverse tasks concurrently. Second, since graph coloring is closely related to the presence of cliques in a graph, the significance of node coloring information to the problem of identifying protein complexes, i.e. dense subgraphs in a PPI network, is investigated. We find that for PPI networks where 1% to 11% of nodes participate in at least one identified protein complex, such as H. sapien (DIP20070219, DIP20081014 and HPRD070609), DSATUR (a well-known complete graph coloring algorithm) node coloring information can improve the quality (homogeneity and separation) of initial candidate complexes. This finding may help to improve existing protein complex detection methods, and/or suggest new methods.

Abstract:
The evolution of the telecommunication technology, such as mobile telecommunication equipment, radio, television, teleconferencing, etc necessitated the existence of numerously broadcast channels. However the corresponding frequencies may interfere for reason of distance, geographical or atmospherical structure or for a variety of other factors. In the present paper we give the definition of the graph radio coloring concept which is a graph coloring generalization. We also introduce radio coloring invariants which are of a great practical importance to problems regarding the allocation of diverse frequencies in order to avoid interference occurrences between channel transmissions. A heuristic algorithm that finds approximate values of the radio chromatic number and radio chromatic cost of a given graph is developed and the result of a computational experiment of the proposed algorithm is given. .

Abstract:
The graph coloring problem is often investigated in the literature. Many insights about many neighboring solutions with the same fitness value are raised but as far as we know, no deep analysis of this neutrality has ever been conducted in the literature. In this paper, we quantify the neutrality of some hard instances of the graph coloring problem. This neutrality property has to be detected as it impacts the search process. Indeed, local optima may belong to plateaus that represents a barrier for local search methods. In this work, we also aim at pointing out the interest of exploiting neutrality during the search. Therefore, a generic local search dedicated to neutral problems, NILS, is performed on several hard instances.

Abstract:
Under the precondition of interrelations among cells in dynamic manufacturing alliance (DMA),this is, the relations are parallel, sequential and cross. A new concept raised, that is minimal complete cells graph (Min-CCG). The main task of this thesis is to proof two hypotheses, i.e. the number of vertex of Min-CCG and the synergy of DMA system. All the above is the necessary base for search the key solution of organizational mechanism of DMA?

Abstract:
\noindent Let $G$ be a simple graph. For any $k\in N$, the $k-$power of $G$ is a simple graph $G^k$ with vertex set $V(G)$ and edge set $\{xy:d_G(x,y)\leq k\}$ and the $k-$subdivision of $G$ is a simple graph $G^{\frac{1}{k}}$, which is constructed by replacing each edge of $G$ with a path of length $k$. So we can introduce the $m-$power of the $n-$subdivision of $G$, as a fractional power of $G$, that is denoted by $G^{\frac{m}{n}}$. In other words $G^{\frac{m}{n}}:=(G^{\frac{1}{n}})^m$. \noindent In this paper some results about the coloring of $G^{\frac{m}{n}}$ are presented when $G$ is a simple and connected graph and $\frac{m}{n}<1$.

Abstract:
Differential evolution was developed for reliable and versatile function optimization. It has also become interesting for other domains because of its ease to use. In this paper, we posed the question of whether differential evolution can also be used by solving of the combinatorial optimization problems, and in particular, for the graph coloring problem. Therefore, a hybrid self-adaptive differential evolution algorithm for graph coloring was proposed that is comparable with the best heuristics for graph coloring today, i.e. Tabucol of Hertz and de Werra and the hybrid evolutionary algorithm of Galinier and Hao. We have focused on the graph 3-coloring. Therefore, the evolutionary algorithm with method SAW of Eiben et al., which achieved excellent results for this kind of graphs, was also incorporated into this study. The extensive experiments show that the differential evolution could become a competitive tool for the solving of graph coloring problem in the future.

Abstract:
This paper studies the kernelization complexity of graph coloring problems with respect to certain structural parameterizations of the input instances. We are interested in how well polynomial-time data reduction can provably shrink instances of coloring problems, in terms of the chosen parameter. It is well known that deciding 3-colorability is already NP-complete, hence parameterizing by the requested number of colors is not fruitful. Instead, we pick up on a research thread initiated by Cai (DAM, 2003) who studied coloring problems parameterized by the modification distance of the input graph to a graph class on which coloring is polynomial-time solvable; for example parameterizing by the number k of vertex-deletions needed to make the graph chordal. We obtain various upper and lower bounds for kernels of such parameterizations of q-Coloring, complementing Cai's study of the time complexity with respect to these parameters. Our results show that the existence of polynomial kernels for q-Coloring parameterized by the vertex-deletion distance to a graph class F is strongly related to the existence of a function f(q) which bounds the number of vertices which are needed to preserve the NO-answer to an instance of q-List-Coloring on F.

Abstract:
A graph is equitably $k$-colorable if its vertices can be partitioned into $k$ independent sets in such a~way that the number of vertices in any two sets differ by at most one. The smallest $k$ for which such a~coloring exists is known as the \emph{equitable chromatic number} of $G$ and denoted by $\chi_{=}(G)$. It is interesting to note that if a graph $G$ is equitably $k$-colorable, it does not imply that it is equitably $(k+1)$-colorable. The smallest integer $k$ for which $G$ is equitably $k'$-colorable for all $k'\geq k$ is called \emph{the equitable chromatic threshold} of $G$ and denoted by $\chi_{=}^{*}(G)$. In the paper we establish the equitable chromatic number and the equitable chromatic threshold for certain products of some highly-structured graphs. We extend the results from [2] for Cartesian, weak and strong tensor products.