We consider reaction-diffusion equations driven by the $ p $-Laplacian on noncompact, infinite volume manifolds assumed to support the Sobolev inequality and, in some cases, to have $ L^2 $ spectrum bounded away from zero, the main example we have in mind being the hyperbolic space of any dimension. It is shown that, under appropriate conditions on the parameters involved and smallness conditions on the initial data, global in time solutions exist and suitable smoothing effects, namely explicit bounds on the $ L^infty $ norm of solutions at all positive times, in terms of $ L^q $ norms of the data. The geometric setting discussed here requires significant modifications w.r.t. the Euclidean strategies.
我们考虑由$ p $ -拉普拉斯驱动的反应扩散方程,在非紧化的无限体积流形上,假设支持Sobolev不等式,并且在某些情况下,$ L^2 $谱有界于零,我们想到的主要例子是任何维度的双曲空间。结果表明,在所涉及参数的适当条件和初始数据的较小条件下,存在全局的时间解和适当的平滑效果,即在所有正时间解的$ L^infty $范数的显式界,以数据的$ L^q $范数表示。这里讨论的几何设置需要对欧几里得策略进行重大修改。
{"title":"Global existence for reaction-diffusion evolution equations driven by the $ {text{p}} $-Laplacian on manifolds","authors":"G. Grillo, Giulia Meglioli, F. Punzo","doi":"10.3934/mine.2023070","DOIUrl":"https://doi.org/10.3934/mine.2023070","url":null,"abstract":"We consider reaction-diffusion equations driven by the $ p $-Laplacian on noncompact, infinite volume manifolds assumed to support the Sobolev inequality and, in some cases, to have $ L^2 $ spectrum bounded away from zero, the main example we have in mind being the hyperbolic space of any dimension. It is shown that, under appropriate conditions on the parameters involved and smallness conditions on the initial data, global in time solutions exist and suitable smoothing effects, namely explicit bounds on the $ L^infty $ norm of solutions at all positive times, in terms of $ L^q $ norms of the data. The geometric setting discussed here requires significant modifications w.r.t. the Euclidean strategies.","PeriodicalId":54213,"journal":{"name":"Mathematics in Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45848351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We consider the Cauchy problem for the heat diffusion equation in the whole Euclidean space consisting of two media with different constant conductivities, where initially one medium has temperature 0 and the other has temperature 1. Under the assumptions that one medium is bounded and the interface is of class $ C^{2, alpha} $, we show that if the interface is stationary isothermic, then it must be a sphere. The method of moving planes due to Serrin is directly utilized to prove the result.
{"title":"A symmetry theorem in two-phase heat conductors","authors":"Hyeonbae Kang, Shigeru Sakaguchi","doi":"10.3934/mine.2023061","DOIUrl":"https://doi.org/10.3934/mine.2023061","url":null,"abstract":"We consider the Cauchy problem for the heat diffusion equation in the whole Euclidean space consisting of two media with different constant conductivities, where initially one medium has temperature 0 and the other has temperature 1. Under the assumptions that one medium is bounded and the interface is of class $ C^{2, alpha} $, we show that if the interface is stationary isothermic, then it must be a sphere. The method of moving planes due to Serrin is directly utilized to prove the result.","PeriodicalId":54213,"journal":{"name":"Mathematics in Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42417652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study local boundedness for subsolutions of nonlinear nonuniformly elliptic equations whose prototype is given by $ nabla cdot (lambda |nabla u|^{p-2}nabla u) = 0 $, where the variable coefficient $ 0leqlambda $ and its inverse $ lambda^{-1} $ are allowed to be unbounded. Assuming certain integrability conditions on $ lambda $ and $ lambda^{-1} $ depending on $ p $ and the dimension, we show local boundedness. Moreover, we provide counterexamples to regularity showing that the integrability conditions are optimal for every $ p > 1 $.
{"title":"Local boundedness for $ p $-Laplacian with degenerate coefficients","authors":"P. Bella, Mathias Schaffner","doi":"10.3934/mine.2023081","DOIUrl":"https://doi.org/10.3934/mine.2023081","url":null,"abstract":"We study local boundedness for subsolutions of nonlinear nonuniformly elliptic equations whose prototype is given by $ nabla cdot (lambda |nabla u|^{p-2}nabla u) = 0 $, where the variable coefficient $ 0leqlambda $ and its inverse $ lambda^{-1} $ are allowed to be unbounded. Assuming certain integrability conditions on $ lambda $ and $ lambda^{-1} $ depending on $ p $ and the dimension, we show local boundedness. Moreover, we provide counterexamples to regularity showing that the integrability conditions are optimal for every $ p > 1 $.","PeriodicalId":54213,"journal":{"name":"Mathematics in Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45792059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We examine $ L^p $-viscosity solutions to fully nonlinear elliptic equations with bounded-measurable ingredients. By considering $ p_0 < p < d $, we focus on gradient-regularity estimates stemming from nonlinear potentials. We find conditions for local Lipschitz-continuity of the solutions and continuity of the gradient. We survey recent breakthroughs in regularity theory arising from (nonlinear) potential estimates. Our findings follow from – and are inspired by – fundamental facts in the theory of $ L^p $-viscosity solutions, and results in the work of Panagiota Daskalopoulos, Tuomo Kuusi and Giuseppe Mingione [10].
我们研究了具有有界可测成分的完全非线性椭圆方程的L^p -粘度解。通过考虑$ p_0 < p < d $,我们关注于非线性势的梯度正则性估计。我们找到了解的局部lipschitz -连续性和梯度的连续性的条件。我们调查了由(非线性)势估计引起的正则性理论的最新突破。我们的发现遵循并受到L^p -粘度解理论中的基本事实的启发,并在Panagiota Daskalopoulos, Tuomo Kuusi和Giuseppe Mingione bbb的工作中得到结果。
{"title":"Potential estimates for fully nonlinear elliptic equations with bounded ingredients","authors":"Edgard A. Pimentel, Miguel Walker","doi":"10.3934/mine.2023063","DOIUrl":"https://doi.org/10.3934/mine.2023063","url":null,"abstract":"<abstract><p>We examine $ L^p $-viscosity solutions to fully nonlinear elliptic equations with bounded-measurable ingredients. By considering $ p_0 < p < d $, we focus on gradient-regularity estimates stemming from nonlinear potentials. We find conditions for local Lipschitz-continuity of the solutions and continuity of the gradient. We survey recent breakthroughs in regularity theory arising from (nonlinear) potential estimates. Our findings follow from – and are inspired by – fundamental facts in the theory of $ L^p $-viscosity solutions, and results in the work of Panagiota Daskalopoulos, Tuomo Kuusi and Giuseppe Mingione <sup>[<xref ref-type=\"bibr\" rid=\"b10\">10</xref>]</sup>.</p></abstract>","PeriodicalId":54213,"journal":{"name":"Mathematics in Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42399113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}