1. Artificial Intelligence Research Institute (IIIA), Spanish National Research Council (CSIC), Campus UAB s/n, Bellaterra 08193, Spain
2. Departamento de Matemática, Universidad Nacional del Sur (UNS), Bahía Blanca 8000, Argentina and Centre for Logic, Epistemology, and The History of Science (CLE), University of Campinas (UNICAMP), Campinas, SP, 13083-859, Brazil