This volume draws mostly on papers presented at the TRENTO 2009 international workshop on Preferences and Decisions, jointly organized by the University of Trento and the University of Sannio at Benevento (Italy). Since its first edition in 1997, the renowned international workshop series TRENTO aims at providing an informal but effective opportunity for sharing and discussing the recent research developments in the field of preference modeling and decision theory, bringing together some of the world's leading experts in this active interdisciplinary area of research. In particular, the scope of the international workshop TRENTO 2009 covered a wide range of topics, such as preference representation and rationality, machine intelligence and automation in decision making, uncertainty modeling, probabilistic and possibilistic decision models, cooperative game theory and coalition formation, aggregation functions and multicriteria decision making, fuzzy set theory and fuzzy logic for decision making, algebraic structures, quantum dynamics, complex network models and negotiation, interactive dynamics and consensus reaching in multiagent decisions, optimization and operational research for decision making. The contributes have been proposed by authors that are among the most recognized scientists in the respective research domains. This volume also provides an opportunity, to colleagues and friends of Mario Fedrizzi, Benedetto Matarazzo, and Aldo Ventre, for celebrating and thanking them for their continuing and stimulating scientific work.

In the last thirty years Computational Geometry has emerged as a new discipline from the field of design and analysis of algorithms. That dis cipline studies geometric problems from a computational point of view, and it has attracted enormous research interest. But that interest is mostly concerned with Euclidean Geometry (mainly the plane or Eu clidean 3-dimensional space). Of course, there are some important rea sons for this occurrence since the first applieations and the bases of all developments are in the plane or in 3-dimensional space. But, we can find also some exceptions, and so Voronoi diagrams on the sphere, cylin der, the cone, and the torus have been considered previously, and there are manY works on triangulations on the sphere and other surfaces. The exceptions mentioned in the last paragraph have appeared to try to answer some quest ions which arise in the growing list of areas in which the results of Computational Geometry are applicable, since, in practiee, many situations in those areas lead to problems of Com putational Geometry on surfaces (probably the sphere and the cylinder are the most common examples). We can mention here some specific areas in which these situations happen as engineering, computer aided design, manufacturing, geographie information systems, operations re search, roboties, computer graphics, solid modeling, etc."

Decision making is an omnipresent, most crucial activity of the human being, and also of virtually all artificial broadly perceived "intelligent" systems that try to mimic human behavior, reasoning and choice processes. It is quite obvious that such a relevance of decision making had triggered vast research effort on its very essence, and attempts to develop tools and techniques which would make it possible to somehow mimic human decision making related acts, even to automate decision making processes that had been so far reserved for the human beings. The roots of those attempts at a scientific analysis can be traced to the ancient times but - clearly - they have gained momentum in the recent 50 or 100 years following a general boom in science. Depending on the field of science, decision making can be viewed in different ways. The most general view can be that decision making boils down to some cognitive, mental process(es) that lead to the selection of an option or a course of action among several alternatives. Then, looking in a deeper way, from a psychological perspective this process proceeds in the context of a set of needs, preferences, rational choice of an individual, a group of individuals, or even an organization. From a cognitive perspective, the decision making process proceeds in the context of various interactions with the environment.

This Festschrift volume is published in honor of Ferran Hurtado on the occasion of his 60th birthday; it contains extended versions of selected communications presented at the XIV Spanish Meeting on Computational Geometry, held at the University of Alcala, Spain, in June 2011. Ferran Hurtado has played a central role in the Spanish community of Computational Geometry since its very beginning, and the quantity and quality of the international participants in the conference is an indisputable proof of his relevance in the international level. The 26 revised full papers were carefully reviewed and selected from numerous submissions. The papers present original research in computational geometry, in its broadest sense. Topics included are discrete and combinatorial geometry, linear programming applied to geometric problems, geometric algorithms and data structures, theoretical foundations of computational geometry, questions of interest in the implementation of geometric algorithms, and applications of computational geometry.

In the last thirty years Computational Geometry has emerged as a new discipline from the field of design and analysis of algorithms. That dis cipline studies geometric problems from a computational point of view, and it has attracted enormous research interest. But that interest is mostly concerned with Euclidean Geometry (mainly the plane or Eu clidean 3-dimensional space). Of course, there are some important rea sons for this occurrence since the first applieations and the bases of all developments are in the plane or in 3-dimensional space. But, we can find also some exceptions, and so Voronoi diagrams on the sphere, cylin der, the cone, and the torus have been considered previously, and there are manY works on triangulations on the sphere and other surfaces. The exceptions mentioned in the last paragraph have appeared to try to answer some quest ions which arise in the growing list of areas in which the results of Computational Geometry are applicable, since, in practiee, many situations in those areas lead to problems of Com putational Geometry on surfaces (probably the sphere and the cylinder are the most common examples). We can mention here some specific areas in which these situations happen as engineering, computer aided design, manufacturing, geographie information systems, operations re search, roboties, computer graphics, solid modeling, etc."