activity
20122026
most citedUniform upper bound for the number of limit cycles of planar piecewise linear differential systems with two zones separated by a straight line

29 citations · 37 across the 20 of their papers we have counts for

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Showing 2025 · math.DSShow all

6 papers · 2 filters

math.DS2025

Generalized Pseudo-Hopf Bifurcation: Limit Cycle Position and Period

Lucas Queiroz Arakaki, Douglas Novaes, Paulo Santana

We investigate planar piecewise-smooth vector fields with a discontinuity line, focusing on the bifurcation of crossing limit cycles that arise when one of the vector fields is tra…

math.DS2025

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…

math.DS2025

Bounding the number of limit cycles in piecewise linear differential systems: methodology and worked examples

Victoriano Carmona, Fernando Fernández-Sánchez, Douglas D. Novaes

In 2012, Huan and Yang introduced the first piecewise linear differential system with two zones separated by a straight line having at least three limit cycles, serving as a counte…

math.DS2025

Normally hyperbolic limit tori near monodromic singularities in 3D polynomial vector fields

Lucas Queiroz Arakaki, Luiz F. S. Gouveia, Douglas D. Novaes

We investigate the maximal number of normally hyperbolic limit tori in three-dimensional polynomial vector fields of degree , which extends the classical notion of Hilb…

math.DS2025

Normal Hyperbolicity in Secondary Hopf Bifurcations

Pedro C. C. R. Pereira, Douglas D. Novaes

We combine results available in the literature to prove that the torus emerging in a secondary Hopf bifurcation is normally hyperbolic. This result is then applied to establish suf…

math.DS2025

Strict increase in the number of normally hyperbolic limit tori in 3D polynomial vector fields

Lucas Queiroz Arakaki, Douglas D. Novaes

The second part of Hilbert's 16th problem concerns determining the maximum number of limit cycles that a planar polynomial vector field of degree can exhibit. A natural…