Luis’s work is about solving combinatorial optimisation problems (COPs). These are problems involving the satisfaction of a set of given constraints (requirements) while optimising a given resource (e.g. money, time, etc.). He has mostly focused on COPs encountered in the design of optical networks. One of those problems is to place central offices (COs) where the extra capacity needed at each CO to support single failures is minimised. Luis is also interested in computing explanations for unsatisfiable constraint satisfaction problems (which is hard in those decision problems that involve a lots of variables like scheduling surgical procedures in a hospital). Users have often a set of constraints that they want to satisfy but there is no way of satisfying them all. In those cases, it is desirable to explain to the user why it is not possible to find a solution that satisfies all the constraints. One application that he is studying is the computation of explanations for unstable multi-agent systems (relevant in Game Theory). Another research area that Luis is exploring is Parallel Computation of Solution to COPs. COPs approaches require high computation power. The availability of clusters and multi-core computers is growing more common so it makes sense to come up with approaches that reduce computation time by executing independent tasks in parallel.