有三个单项式的复微分方程的更多极限循环

IF 2.4 2区 数学 Q1 MATHEMATICS Journal of Differential Equations Pub Date : 2024-10-18 DOI:10.1016/j.jde.2024.10.013
M.J. Álvarez , B. Coll , A. Gasull , R. Prohens
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More concretely, if <span><math><mi>N</mi><mo>=</mo><mi>max</mi><mo>⁡</mo><mo>(</mo><mi>k</mi><mo>+</mo><mi>l</mi><mo>,</mo><mi>m</mi><mo>+</mo><mi>n</mi><mo>,</mo><mi>p</mi><mo>+</mo><mi>q</mi><mo>)</mo></math></span> and <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>(</mo><mi>N</mi><mo>)</mo><mo>∈</mo><mi>N</mi><mo>∪</mo><mo>{</mo><mo>∞</mo><mo>}</mo></math></span> denotes the maximum number of limit cycles of the above equations, we show that for <span><math><mi>N</mi><mo>≥</mo><mn>4</mn></math></span>, <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>(</mo><mi>N</mi><mo>)</mo><mo>≥</mo><mi>N</mi><mo>−</mo><mn>3</mn></math></span> and that for some values of <em>N</em> this new lower bound is <span><math><mi>N</mi><mo>+</mo><mn>1</mn></math></span>. We also present examples with many limit cycles and different configurations. 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More concretely, if <span><math><mi>N</mi><mo>=</mo><mi>max</mi><mo>⁡</mo><mo>(</mo><mi>k</mi><mo>+</mo><mi>l</mi><mo>,</mo><mi>m</mi><mo>+</mo><mi>n</mi><mo>,</mo><mi>p</mi><mo>+</mo><mi>q</mi><mo>)</mo></math></span> and <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>(</mo><mi>N</mi><mo>)</mo><mo>∈</mo><mi>N</mi><mo>∪</mo><mo>{</mo><mo>∞</mo><mo>}</mo></math></span> denotes the maximum number of limit cycles of the above equations, we show that for <span><math><mi>N</mi><mo>≥</mo><mn>4</mn></math></span>, <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>(</mo><mi>N</mi><mo>)</mo><mo>≥</mo><mi>N</mi><mo>−</mo><mn>3</mn></math></span> and that for some values of <em>N</em> this new lower bound is <span><math><mi>N</mi><mo>+</mo><mn>1</mn></math></span>. We also present examples with many limit cycles and different configurations. 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引用次数: 0

摘要

在本文中,我们改进了复微分方程族中三个单项式 z˙=Azkz¯l+Bzmz¯n+Czpz¯q 的极限循环数的现有下界,几乎翻了一番,k,l,m,n,p,q 为非负整数,A,B,C∈C。更具体地说,如果 N=max(k+l,m+n,p+q),H3(N)∈N∪{∞} 表示上述方程的最大极限循环数,我们将证明对于 N≥4 时,H3(N)≥N-3,并且对于某些 N 值,这一新的下界是 N+1。我们还举例说明了许多极限循环和不同配置。最后,我们证明了 H3(2)≥2,并详细研究了有三个单项式的二次情况,证明了其中某些情况下两个极限循环不存在、唯一或存在。
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More limit cycles for complex differential equations with three monomials
In this paper we improve, by almost doubling, the existing lower bound for the number of limit cycles of the family of complex differential equations with three monomials, z˙=Azkz¯l+Bzmz¯n+Czpz¯q, being k,l,m,n,p,q non-negative integers and A,B,CC. More concretely, if N=max(k+l,m+n,p+q) and H3(N)N{} denotes the maximum number of limit cycles of the above equations, we show that for N4, H3(N)N3 and that for some values of N this new lower bound is N+1. We also present examples with many limit cycles and different configurations. Finally, we show that H3(2)2 and study in detail the quadratic case with three monomials proving in some of them non-existence, uniqueness or existence of exactly two limit cycles.
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来源期刊
CiteScore
4.40
自引率
8.30%
发文量
543
审稿时长
9 months
期刊介绍: The Journal of Differential Equations is concerned with the theory and the application of differential equations. The articles published are addressed not only to mathematicians but also to those engineers, physicists, and other scientists for whom differential equations are valuable research tools. Research Areas Include: • Mathematical control theory • Ordinary differential equations • Partial differential equations • Stochastic differential equations • Topological dynamics • Related topics
期刊最新文献
The existence and multiplicity of symmetrical periodic solutions for asymptotically linear distributed delay differential systems Stochastic and deterministic parabolic equations with bounded measurable coefficients in space and time: Well-posedness and maximal regularity Full asymptotic expansion of the permeability matrix of a dilute periodic porous medium Non-uniqueness of admissible weak solutions to the two-dimensional pressureless Euler system Neumann problem for fractional Ginzburg-Landau equation on a upper- right quarter plane
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