Advances in artificial intelligence 19th Conference of the Spanish Association for Artificial Intelligence, CAEPIA 2020/2021, Málaga, Spain, September 22–24, 2021 : proceedings - Alba, Enrique; Luque, Gabriel; Chicano, Francisco; Cotta, Carlos; Camacho, David; Ojeda-Aciego, Manuel; Montes, Susana; Troncoso, Alicia; Riquelme, José; Gil-Merino, Rodrigo (Lecture Notes in computer science, 2021)