An acyclic edge colouring of a graph is a proper edge colouring having no 2-coloured cycle, that is, a colouring in which the union of any two colour classes forms a linear forest. The acyclic chromatic index of a graph is the minimum number k such that there is an acyclic edge colouring using k colours and is usually denoted by a′(G). Determining a ′(G) exactly is a very hard problem (both the...

Software watermarking involves embedding a unique identifier within a piece of software, to discourage software theft. The global revenue loss due to software piracy was estimated to be more than $50 billion in 2008. We survey the proposed register allocation based algorithms for software watermarking. This family of static watermarks are constraint-based and embed the watermark in a solution t...

Producing good quality examination timetables is a difficult task which is faced by many academic institutions. Due to the complexity and the large size of the realworld university examination timetabling problems, it is difficult to obtain an optimal solution. Indeed, due to the complex nature of the problem, it is questionable if an end user would recognise a truly optimal solution. Carter an...

For integer q ≥ 2, we derive edge q-colouring models for (i) the Tutte polynomial of a graph G on the hyperbola H q , (ii) the symmetric weight enumerator for group-valued q-flows of G, and (iii) a more general vertex colouring model partition function that includes these polynomials and the principal specialization order q of Stanley's symmetric monochrome polynomial. We describe the general r...

1.1 The Problem Let G = (V,E) be a simple undirected graph. A vertex colouring of G assigns colours to each vertex in such a way that neighbours have different colours. In this paper we discuss how efficient (time and bits) vertex colouring may be accomplished by exchange of bits between neighbouring vertices. The distributed complexity of vertex colouring is of fundamental interest for the stu...

We introduce the Distributed Guided Local Search (DistGLS) algorithm for solving Distributed Constraint Satisfaction Problems. Our algorithm is based on the centralised Guided Local Search algorithm, which is extended with additional heuristics in order to enhance its efficiency in distributed scenarios. We discuss the strategies we use for dealing with local optima in the search for solutions ...