2 papers
math.CA2023
Algebraic Multiplicity and the Poincaré Problem
Jinzhi Lei, Lijun Yang
In this paper we derive an upper bound for the degree of the strict invariant algebraic curve of a polynomial system in the complex project plane under generic condition. The resul…
math.CA2017
Limit cycles by perturbing quadratic isochronous centers inside piecewise smooth polynomial differential systems
Xiuli Cen, Lijun Yang, Meirong Zhang
In the present paper, we study the number of zeros of the first order Melnikov function for piecewise smooth polynomial differential system, to estimate the number of limit cycles…