I am very grateful to my supervisor Dr. Pedro Barahona 1 who, in spite of his tight schedule, found time to guide and help me with his agile mind to overcome the obstacles throughout the whole development of the present dissertation. Also I am in debt with João Almeida 2 who first proposed the Species Differentiation Problem and provided clarification about the biological aspects with which this thesis is concerned. My Master studies were supported by the European Master’s Program in Computational Logic (EMCL) without which it would have been impossible to study in Europe. Finally I must thank my girlfriend, family and friends for their continuous support, and my colleague and friend Luciano without whom it would have been hard to keep focus on the work
