The domination number of a graph G = (V,E) is the minimum size of a dominating set U ⊆ V , which satisfies that every vertex in V \U is adjacent to at least one vertex in U . The notion of a problem kernel refers to a polynomial time algorithm that achieves some provable reduction of the input size. Given a graph G whose domination number is k, the objective is to design a polynomial time algor...

We study the possibility that large scale cosmological perturbations have been generated during the domination and decay of a massive particle species whose mass depends on the expectation value of a light scalar field. We discuss the constraints that must be imposed on the field in order to remain light and on the annihilation cross section and decay rate of the massive particles in order for ...

a roman dominating function (rdf) on a graph g = (v,e) is defined to be a function satisfying the condition that every vertex u for which f(u) = 0 is adjacent to at least one vertex v for which f(v) = 2. a set s v is a restrained dominating set if every vertex not in s is adjacent to a vertex in s and to a vertex in . we define a restrained roman dominating function on a graph g = (v,e) to be ...

An independent set of vertices S of a graph dominates the graph efficiently if every vertex of the graph is either in S or has precisely one neighbour in S. In this paper we prove that a connected cubic vertex-transitive graph on a power of 2 vertices has a set that dominates it efficiently if and only if it is not isomorphic to a Möbius ladder. This is a preprint of an article accepted for pub...

The linear programmimg formulations of graph domination and graph packing are duals. Likewise, fractional efficient domination for a graph G has as its dual the parameter discussed in this paper, namely the minimum weight of a real-valued function f : V(G) -+ [0, (0) such that the sum of the weights in each closed neighborhood is at least its cardinality. The fractional and integer "closed neig...

Investment in stock market involves many decision rules and variables; hence investors are increasingly relying on ratings provided by rating agencies to guide their stock selections. However, do these stocks ratings have information value? Are rating agencies’ ratings valid? We research these questions by analyzing the performance of rating agencies. This study provides empirical evidence on t...

The last years there is an increasing interest for query processing techniques that take into consideration the dominance relationship between items to select the most promising ones, based on user preferences. Skyline and top-k dominating queries are examples of such techniques. A skyline query computes the items that are not dominated, whereas a top-k dominating query returns the k items with...