Non-bifurcation of critical periods from semi-hyperbolic polycycles of quadratic centres

In this paper we consider the unfolding of saddle-node X=1xUa(x,y)(x(xμ-ε)∂x-Va(x)y∂y), parametrized by (ε,a) with ε≈0 and a in an open subset A of Rα, and we study the Dulac time T(s;ε,a) of one of its hyperbolic sectors. We prove (theorem 1.1) that the derivative ∂sT(s;ε,a) tends to -∞ as (s,ε)→(0...

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Bibliographic Details
Authors: Marín, David|||0000-0003-4422-6418, Saavedra, M., Villadelprat Yagüe, Jordi|||0000-0002-1168-9750
Format: article
Publication Date:2023
Country:España
Institution:Universitat Autònoma de Barcelona
Repository:Dipòsit Digital de Documents de la UAB
Language:English
OAI Identifier:oai:ddd.uab.cat:257112
Online Access:https://ddd.uab.cat/record/257112
https://dx.doi.org/urn:doi:10.1017/prm.2021.72
Access Level:Open access
Keyword:Period function
Saddle-node unfolding
Dulac time
Asymptotic expansions
Description
Summary:In this paper we consider the unfolding of saddle-node X=1xUa(x,y)(x(xμ-ε)∂x-Va(x)y∂y), parametrized by (ε,a) with ε≈0 and a in an open subset A of Rα, and we study the Dulac time T(s;ε,a) of one of its hyperbolic sectors. We prove (theorem 1.1) that the derivative ∂sT(s;ε,a) tends to -∞ as (s,ε)→(0+,0) uniformly on compact subsets of A. This result is addressed to study the bifurcation of critical periods in the Loud's family of quadratic centres. In this regard we show (theorem 1.2) that no bifurcation occurs from certain semi-hyperbolic polycycles.