New Exploration of Phase Portrait Classification of Quadratic Polynomial Differential Systems Based on Invariant Theory

After linear differential systems in the plane, the easiest systems are quadratic polynomial differential systems in the plane. Due to their nonlinearity and their many applications, these systems have been studied by many authors. Such quadratic polynomial differential systems have been divided int...

Descripción completa

Detalles Bibliográficos
Autores: Artés Ferragud, Joan Carles|||0000-0003-4332-7495, Cairó, Laurent, Llibre, Jaume|||0000-0002-9511-5999
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:313634
Acceso en línea:https://ddd.uab.cat/record/313634
https://dx.doi.org/urn:doi:10.3390/appliedmath5020068
Access Level:acceso abierto
Palabra clave:Quadratic vector field
Quadratic system
Phase portrait
Descripción
Sumario:After linear differential systems in the plane, the easiest systems are quadratic polynomial differential systems in the plane. Due to their nonlinearity and their many applications, these systems have been studied by many authors. Such quadratic polynomial differential systems have been divided into ten families. Here, for two of these families, we classify all topologically distinct phase portraits in the Poincaré disc. These two families have already been studied previously, but several mistakes made there are repaired here thanks to the use of a more powerful technique. This new technique uses the invariant theory developed by the Sibirskii School, applied to differential systems, which allows to determine all the algebraic bifurcations in a relatively easy way. Even though the goal of obtaining all the phase portraits of quadratic systems for each of the ten families is not achievable using only this method, the coordination of different approaches may help us reach this goal.