Polynomial differential systems with invariant algebraic curves of arbitrary degree formed by Legendre polynomials
Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques)
Valls, Clàudia 1973- (Universidade de Lisboa. Instituto Superior Técnico. Departamento de Matemática)

Date:	2025
Abstract:	In 1891 Poincaré asked: Given m ≥ 2, is there a positive integer M(m) such that if a polynomial differential system of degree m has an invariant algebraic curve of degree ≥ M(m), then it has a rational first integral? Brunella and Mendes repeated the same open question in 2000, and Lins-Neto in 2002. Between the years 2001 and 2003 three different families of quadratic polynomial differential systems provided a negative answer to this question. One of the answers used the Hermite polynomials. Recently a new negative answer was provided for polynomial differential systems of arbitrary degree using the Laguerre polynomials. In this paper we provide another new negative answer but using for first time the Legendre polynomials. So the orthogonal polynomials play a role in the Poincaré's question. Moreover we classify the phase portraits of these polynomial differential systems having invariant algebraic curves of arbitrary degree based on the Legendre polynomials.
Grants:	Agencia Estatal de Investigación PID2022-136613NB-I00 Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-00113
Note:	Altres ajuts: Reial Acadèmia de Ciències i Arts de Barcelona
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Polynomial differential systems ; Invariant algebraic curve ; Rational first integral ; Hermite polynomials ; Laguerre polynomials ; Legendre polynomials
Published in:	Journal of Pure and Applied Algebra, Vol. 229, Issue 8 (August 2025) , art. 108001, ISSN 0022-4049

DOI: 10.1016/j.jpaa.2025.108001

Available from: 2027-08-31 Postprint

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > GSD (Dynamical systems)
Articles > Research articles
Articles > Published articles