Electron. J. Differential Equations, Vol. 2026 (2026), No. 74, pp. 1-19.

Dynamics of piecewise linear Lienard systems near infinity

Man Jia, Yuhao Meng

Abstract:
In this article, we study the dynamics near infinity for a class of piecewise linear Lienard systems \({\mathrm{d}x}/{\mathrm{d}t}=y-F(x)\), \({\mathrm{d}y}/{\mathrm{d}t}=-g(x)\), with \(n\) parallel switching lines, where \(F(x)\) and \(g(x)\) may be continuous or discontinuous. Using the qualitative theory of differential equations, we obtain a complete classification of the phase portraits near infinity in the Poincare disc. More precisely, when equilibria exist on the equator of the Poincare disc, we show that the dynamics near infinity are determined by the two outermost linear systems. When no equilibrium exists on the equator, a center-focus problem arises at infinity. In this case, we provide sufficient conditions for the dynamics near infinity to be a stable focus or an unstable focus, and derive a necessary condition for the dynamics near infinity to be a center. Furthermore, for the continuous case where the system has a unique finite equilibrium, we establish a global center criterion.

Submitted March 6, 2026. Published September 28, 2026.
Math Subject Classifications: 34C07, 34D20, 37C20.
Key Words: Piecewise linear Lienard system; Poincare compactification; center-focus problem.
DOI: 10.58997/ejde.2026.74

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Man Jia
School of Mathematics and Statistics
Fuzhou University
Fuzhou 350116, Fujian, China
email: manjia@fzu.edu.cn
Yuhao Meng
School of Mathematics and Statistics
HNP-LAMA, Central South University
Changsha 410083, Hunan, China
email: yuhao_meng@csu.edu.cn

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