In this work we study Lie symmetries of planar quasihomogeneous polynomialvector fields from different points of view, showing its integrability. Additionally, we show thatcertain perturbations of such vector fields w...In this work we study Lie symmetries of planar quasihomogeneous polynomialvector fields from different points of view, showing its integrability. Additionally, we show thatcertain perturbations of such vector fields which generalize the so–called degenerate infinityvector fields are also integrable.展开更多
We characterize the Liouvillian and analytic integrability of the quadratic polynomial vector fields in R2 having an invariant ellipse.More precisely,a quadratic system having an invariant ellipse can be written into ...We characterize the Liouvillian and analytic integrability of the quadratic polynomial vector fields in R2 having an invariant ellipse.More precisely,a quadratic system having an invariant ellipse can be written into the form x=x2＋y2-1＋y（ax＋by＋c）,y=x（ax＋by＋c）,and the ellipse becomes x2＋y2=1.We prove that（i） this quadratic system is analytic integrable if and only if a=0;（ii） if x2＋y2=1 is a periodic orbit,then this quadratic system is Liouvillian integrable if and only if x2＋y2=1 is not a limit cycle;and（iii） if x2＋y2=1 is not a periodic orbit,then this quadratic system is Liouvilian integrable if and only if a=0.展开更多
基金supported by the Spanish MCYT,Grant Number BFM 2002-04236-C01-01
文摘In this work we study Lie symmetries of planar quasihomogeneous polynomialvector fields from different points of view, showing its integrability. Additionally, we show thatcertain perturbations of such vector fields which generalize the so–called degenerate infinityvector fields are also integrable.
基金Supported by the Natural Science Foundation of Anhui Education Committee(KJ2007A003)the"211 Project"for Academic Innovative Teams of Anhui University(KJTD002B)+4 种基金the Doctoral Scientific Research Project for Anhui Medical University(XJ201022)the Key Project for Hefei Normal University(2010kj04zd)the Provincial Excellent Young Talents Foundation for Colleges and Universities of Anhui Province(2011SQRL126)the Academic Innovative Scientific Research Project of Postgraduates for Anhui University(yfc100020yfc100028)
基金partially supported by the MINECO/FEDER(Grant No.MTM2008–03437)AGAUR(Grant No.2009SGR-410)+1 种基金ICREA Academia and FP7-PEOPLE-2012-IRSES 316338 and 318999supported by Portuguese National Funds through FCT-Fundao para a Ciência e a Tecnologia within the project PTDC/MAT/117106/2010 and by CAMGSD
文摘We characterize the Liouvillian and analytic integrability of the quadratic polynomial vector fields in R2 having an invariant ellipse.More precisely,a quadratic system having an invariant ellipse can be written into the form x=x2＋y2-1＋y（ax＋by＋c）,y=x（ax＋by＋c）,and the ellipse becomes x2＋y2=1.We prove that（i） this quadratic system is analytic integrable if and only if a=0;（ii） if x2＋y2=1 is a periodic orbit,then this quadratic system is Liouvillian integrable if and only if x2＋y2=1 is not a limit cycle;and（iii） if x2＋y2=1 is not a periodic orbit,then this quadratic system is Liouvilian integrable if and only if a=0.
