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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Detalles Bibliográficos
Autores: Marín, David|||0000-0003-4422-6418, Saavedra, M., Villadelprat Yagüe, Jordi|||0000-0002-1168-9750
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:257112
Acceso en línea:https://ddd.uab.cat/record/257112
https://dx.doi.org/urn:doi:10.1017/prm.2021.72
Access Level:acceso abierto
Palabra clave:Period function
Saddle-node unfolding
Dulac time
Asymptotic expansions
Descripción
Sumario: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.