Let M be an additive abelian group. An M-strong-oriented coloring of an oriented graph G is a mapping φ from V (G) to M such that φ(u) 6= φ(v) whenever −→uv is an arc in G and φ(v)−φ(u) 6= −(φ(t)−φ(z)) whenever −→uv and zt are two arcs in G. The strong oriented chromatic number of an oriented graph is the minimal order of a group M such that G has an M-strong-oriented coloring. This notion was ...

We discuss methods for the generation of oriented matroids and of isomorphism classes of oriented matroids. Our methods are based on single element extensions and graph theoretical representations of oriented matroids, and all these methods work in general rank and for nonuniform and uniform oriented matroids as well. We consider two types of graphs, cocircuit graphs and tope graphs, and discus...

We introduce two notions, (i)oriented labelling and (ii) oriented labelling, to explore frequency assignment problem under halfduplex setting and compute bounds of oriented labelling of special classes of graphs : trees, bipartite graphs and planar graphs. We do study an oriented version of clique cover problem as well. The frequency assignment problem (FAP) arises in wireless communication sys...

An oriented graph is a directed graph without any cycle of length at most 2. To push a vertex of a directed graph is to reverse the orientation of the arcs incident to that vertex. Klostermeyer and MacGillivray defined push graphs which are equivalence class of oriented graphs with respect to vertex pushing operation. They studied the homomorphism of the equivalence classes of oriented graphs w...

let $g$ be a simple graph‎, ‎and $g^{sigma}$‎ ‎be an oriented graph of $g$ with the orientation ‎$sigma$ and skew-adjacency matrix $s(g^{sigma})$‎. ‎the $k-$th skew spectral‎ ‎moment of $g^{sigma}$‎, ‎denoted by‎ ‎$t_k(g^{sigma})$‎, ‎is defined as $sum_{i=1}^{n}( ‎‎‎lambda_{i})^{k}$‎, ‎where $lambda_{1}‎, ‎lambda_{2},cdots‎, ‎lambda_{n}$ are the eigenvalues of $g^{sigma}$‎. ‎suppose‎ ‎$g^{sigma...

Program slicing has many applications in software engineering activities including program comprehension, debugging, testing, maintenance, and model checking. In this paper, we propose an approach to slicing aspect-oriented software. To solve this problem, we present a dependencebased representation called aspect-oriented system dependence graph (ASDG), which extends previous dependence graphs,...

The oriented diameter of a bridgeless connected undirected (bcu ) graph G is the smallest diameter among all the diameters of strongly connected orientations of G. We study algorithmic aspects of determining the oriented diameter of a chordal graph. We (a) construct a linear-time approximation algorithm that, for a given chordal bcu graph G, finds a strongly connected orientation of G with diam...

We show that to each graceful labelling of a path on 2s + 1 vertices, s ≥ 2, there corresponds a current assignment on a 3-valent graph which generates at least 22s cyclic oriented triangular embeddings of a complete graph on 12s + 7 vertices. We also show that in this correspondence, two distinct graceful labellings never give isomorphic oriented embeddings. Since the number of graceful labell...

The agent paradigm can be seen as an extension of the notion of (active) objects by concepts like autonomy and cooperation. Mainstream object-oriented modeling techniques do not account for these agent-speci4c aspects. Therefore, dedicated techniques for agent-oriented modeling are required which are based on the concepts and notations of object-oriented modeling and extend these in order to su...