Tác giả: Valentín Ramírez

Jaume Llibre is full professor at the Autonomous University of Barcelona (Spain) and a member of the Royal Academy of Sciences and Arts of Barcelona. He was a long-term visitor at different universities and research institutes. He is the author of many papers and has a large number of collaborators and Ph.D. students. His main results deal with periodic orbits, integrability, averaging theory, polynomial vector fields, Hamiltonian systems, celestial mechanics, and topological entropy. Rafael Ramírez studied at the Peoples Friendship University (UDN) and read his Ph D thesis under the direction of Professor A.C. Galiullin. He is a professor at the Rovira i Virgili University of Tarragona (Spain) and is a collaborator of Ph D students. His main results deal with the inverse problem of ordinary differential equations, mechanics, and nonholonomic systems. Valentín Ramírez studied at the University of Barcelona and read his Ph D thesis under the direction of Professor J. Llibre. His main results deal with qualitative theory of ordinary differential equations, in particular with the center-focus problem, integrability, and development of mathematical models of financial risks.