数学物理学报 ›› 2020, Vol. 40 ›› Issue (1): 63-71.

• 论文 • 上一篇    下一篇

紧黎曼流形上Hardy-Littlewood-Sobolev不等式的极值问题:次临界逼近法

张书陶,韩亚洲*()   

  1. 中国计量学院数学系 杭州 310018
  • 收稿日期:2019-03-13 出版日期:2020-02-26 发布日期:2020-04-08
  • 通讯作者: 韩亚洲 E-mail:yazhou.han@gmail.com
  • 基金资助:
    国家自然科学基金(11201443);浙江省自然科学基金(LY18A010013)

Extremal Problems of Hardy-Littlewood-Sobolev Inequalities on Compact Riemannian Manifolds: the Approximation Method from Subcritical to Critical

Shutao Zhang,Yazhou Han*()   

  1. Department of Mathematics, College of Science, China Jiliang University, Hangzhou 310018
  • Received:2019-03-13 Online:2020-02-26 Published:2020-04-08
  • Contact: Yazhou Han E-mail:yazhou.han@gmail.com
  • Supported by:
    国家自然科学基金(11201443);浙江省自然科学基金(LY18A010013)

摘要:

令(Mng)为n维无边紧黎曼流形, $0<\alpha<n,\ q>\frac{n}{n-\alpha}$,该文研究了下列Hardy-Littlewood-Sobolev(HLS)不等式

的极值问题.首先,利用算子$I_\alpha: L^p(M^n)\rightarrow L^q(M^n)$在次临界情形(即$p>\frac{nq}{n+\alpha q}$)时的紧致性,证明$p>\frac{nq}{n+\alpha q}$时极值函数$f_p\in L^p(M^n)$的存在性;进而证明函数列$\{f_p\}$为临界情形时HLS不等式的最佳常数的极值列;最后,结合极值列$\{f_p\}$在$L^{\frac{nq}{n+\alpha q}}(M^n)$中的一致有界性,利用文献[32]建立的集中列紧原理证明$\{f_p\}$在$L^{\frac{nq}{n+\alpha q}}(M^n)$中存在收敛子列,从而给出临界情形(即$p=\frac{nq}{n+\alpha q}$)时极值函数的存在性.

关键词: Hardy-Littlewood-Sobolev不等式, 紧黎曼流形, 极值问题

Abstract:

Let $(M^n,g)$ be a $n$-dimensional compact Riemannian manifolds, $0<\alpha<n$ and $q>\frac{n}{n-\alpha}$. This paper is mainly devoted to study the extremal problems of the following HLS inequalities:

Firstly, we prove that $I_\alpha: L^p(M^n)\rightarrow L^q(M^n)$ with $p>\frac{nq}{n+\alpha q}$ is compact and then get the existence of extremal functions $f_p, p>\frac{nq}{n+\alpha q}$. Secondly, we find that the function sequence $\{f_p\}$ is a maximizing sequence for the sharp constant of HLS inequality with $p=\frac{nq}{n+\alpha q}$. Finally, by the Concentration-Compactness principle established in [32], we can prove that there exists a convergence subsequence of $\{f_p\}$ and then give the existence of extremal function for critical case.

Key words: Hardy-Littlewood-Sobolev intqualities, Compact Riemannian manifolds, Extremal problems

中图分类号: 

  • O175.2