64 citations · 81 across the 10 of their papers we have counts for
11 papers
Weak-Coppel problem for a class of Riccati differential equations
Armengol Gasull, Douglas D. Novaes, Joan Torregrosa
We study the -periodic solutions of the real Riccati differential equation where and is a -periodic function. Our goal is to define a real-val…
On the number of limit cycles in piecewise planar quadratic differential systems
Francisco Braun, Leonardo P. C. da Cruz, Joan Torregrosa
We consider piecewise quadratic perturbations of centers of piecewise quadratic systems in two zones determined by a straight line through the origin. By means of expansions of the…
Time-reversibility and integrability of p:-q resonant vector fields
Jaume Gine, Valery G. Romanovski, Joan Torregrosa
We study local analytical integrability in a neighborhood of resonant singular point of a two-dimensional vector field and its connection to time-reversibility with respect…
Bifurcation of limit cycles in piecewise quadratic differential systems with an invariant straight line
Leonardo P. C. da Cruz, Joan Torregrosa
We solve the center-focus problem in a class of piecewise quadratic polynomial differential systems with an invariant straight line. The separation curve is also a straight line wh…
Limit cycles from a monodromic infinity in planar piecewise linear systems
Emilio Freire, Enrique Ponce, Joan Torregrosa +1
Planar piecewise linear systems with two linearity zones separated by a straight line and with a periodic orbit at infinity are considered. By using some changes of variables and p…
New lower bound for the Hilbert number in piecewise quadratic differential systems
Leonardo P. C. da Cruz, Douglas D. Novaes, Joan Torregrosa
We study the number of limit cycles bifurcating from a piecewise quadratic system. All the differential systems considered are piecewise in two zones separated by a straight line.…