The study of the limit cycles is one of the most important objectives in the qualitative theoryof the planar ordinary differential equations. We remark that to obtain an upper bound for themaximum number of limit cycles for a given differential system in the plane R2, in general, is a very difficult problem. The study of the discontinuous piecewise differential systems, morerecently also called Filippov systems, has attracted the attention of the mathematicians during these past decades due to their applications. These piecewise differential systems in the plane are formed by different differential systems defined in distinct regions separated by a curve. A pioneering work on this subject was due to Andronov, Vitt and Khaikin in 1920's, and later onFilippov in 1988 provided the theoretical bases for this kind of differential systems. As for the smooth differential systems the study of the existence and location of limit cycles in the piecewise differential systems is also of great importance.The main tools for computing analytically limit cycles of differential systems are based on theaveraging theory, the Melnikov integral, the Poincaré map, the Poincaré map together with theNewton-Kantorovich Theorem or the Poincaré-Miranda theorem, and the use of the first integralsof the differential systems for computing their limit cycles.The objective of this project will be the study of the limit cycles of some relevant classes ofdiscontinuous piecewise differential systems in the plane R2 and in the space R3. Our tools forstudying such limit cycles will be the averaging theory when we do not know the first integrals ofthe differential systems which form the discontinuous piecewise differential systems, and the first integrals when these are knwon.
News published in Agência FAPESP Newsletter about the scholarship: