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Mathematics 2010
Rapid evolution of complex limit cyclesAbstract: The current article studies certain problems related to complex cycles of holomorphic foliations with singularities in the complex plane. We focus on the case when polynomial differential one-form gives rise to a foliation by Riemann surfaces. In this setting, a complex cycle is defined as a nontrivial element of the fundamental group of a leaf from the foliation. Whenever the polynomial foliation comes from a perturbation of an exact one-form, one can introduce the notion of a multi-fold cycle. This type of cycle has at least one representative that determines a free homotopy class of loops in an open fibered subdomain of the complex plane. The topology of this subdomain is closely related to the exact one-form mentioned earlier. We introduce and study the notion of multi-fold cycles of a close-to-integrable polynomial foliation. We also explore how these cycles correspond to periodic orbits of a certain Poincar\'e map associated with the foliation. Finally, we discuss the tendency of a continuous family of multi-fold limit cycles to escape from certain large open domains in the complex plane as the foliation converges to its integrable part.
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