This conference is supported by the Portuguese Foundation for Science and Technology (FCT - Fundação para a Ciência e a Tecnologia), throught The Center for Research and Development in Mathematics and Applications (CIDMA) - projects UIDB/04106/2020 and UIDP/04106/2020 - and throught The Centro de Matemática, Aplicações Fundamentais e Investigação Operacional (CMAFcIO) - project UIDB/04561/2020.