{"title":"Weighted estimates for the Laplacian on the cubic lattice","authors":"E. Korotyaev, J. S. Møller","doi":"10.4310/arkiv.2019.v57.n2.a8","DOIUrl":"https://doi.org/10.4310/arkiv.2019.v57.n2.a8","url":null,"abstract":"We consider the discrete Laplacian Δ on the cubic lattice Zd, and deduce estimates on the group eitΔ and the resolvent (Δ−z)−1, weighted by q(Zd)-weights for suitable q 2. We apply the obtained results to discrete Schrödinger operators in dimension d 3 with potentials from p(Zd) with suitable p 1.","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Capacitary differentiability of potentials of finite Radon measures","authors":"J. Verdera","doi":"10.4310/arkiv.2019.v57.n2.a10","DOIUrl":"https://doi.org/10.4310/arkiv.2019.v57.n2.a10","url":null,"abstract":"We study differentiability properties of a potential of the type $Kstar mu$, where $mu$ is a finite Radon measure in $mathbb{R}^N$ and the kernel $K$ satisfies $|nabla^j K(x)| le C, |x|^{-(N-1+j)}, quad j=0,1,2.$ \u0000We introduce a notion of differentiability in the capacity sense, where capacity is classical capacity in the de la Vallee Poussin sense associated with the kernel $|x|^{-(N-1)}.$ We require that the first order remainder at a point is small when measured by means of a normalized weak capacity \"norm\" in balls of small radii centered at the point. This implies weak $L^{N/(N-1)}$ differentiability and thus $L^{p}$ differentiability in the Calderon--Zygmund sense for $1le p < N/(N-1)$. We show that $Kstar mu$ is a.e. differentiable in the capacity sense, thus strengthening a recent result by Ambrosio, Ponce and Rodiac. We also present an alternative proof of a quantitative theorem of the authors just mentioned, giving pointwise Lipschitz estimates for $Kstar mu.$ As an application, we study level sets of newtonian potentials of finite Radon measures.","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47693692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Radial variation of Bloch functions on the unit ball of $mathbb{R}^d$","authors":"P. Muller, K. Riegler","doi":"10.4310/arkiv.2020.v58.n1.a10","DOIUrl":"https://doi.org/10.4310/arkiv.2020.v58.n1.a10","url":null,"abstract":"We provide variational estimates for Bloch functions on the unit ball of $mathbb{R}^d$ extending previous work on the Anderson conjecture for conformal maps on the unit disc.","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Injective objects in the category of finitely presented representations of an interval finite quiver","authors":"Pengjie Jiao","doi":"10.4310/ARKIV.2019.v57.n2.a7","DOIUrl":"https://doi.org/10.4310/ARKIV.2019.v57.n2.a7","url":null,"abstract":"We characterize the indecomposable injective objects in the category of finitely presented representations of an interval finite quiver.","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Determining all $(2, 3)$-torus structures of a symmetric plane curve","authors":"R. Kloosterman","doi":"10.4310/ARKIV.2018.V56.N2.A9","DOIUrl":"https://doi.org/10.4310/ARKIV.2018.V56.N2.A9","url":null,"abstract":"In this paper, we describe all (2, 3)-torus structures of a highly symmetric 39-cuspidal degree 12 curve. A direct computer-aided determination of these torus structures seems to be out of reach. We use various quotients by automorphisms to find torus structures. We use a height pairing argument to show that there are no further structures.","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47991270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Inversion d'opérateurs de courbures au voisinage d'une métrique Ricci parallèle II: variétés non compactes à géométrie bornée.","authors":"Erwann Delay","doi":"10.4310/arkiv.2018.v56.n2.a5","DOIUrl":"https://doi.org/10.4310/arkiv.2018.v56.n2.a5","url":null,"abstract":"On considere une variete riemannienne (M,g) non compacte, complete, a geometrie bornee et courbure de Ricci parallele. \u0000Nous montrons que certains operateurs \"affines\" en la courbure de Ricci sont localement \u0000inversibles, dans des espaces de Sobolev classiques, au voisinage de g.","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Uniformly local spaces and refinements of the classical Sobolev embedding theorems","authors":"P. Rabier","doi":"10.4310/ARKIV.2018.V56.N2.A13","DOIUrl":"https://doi.org/10.4310/ARKIV.2018.V56.N2.A13","url":null,"abstract":"We prove that if f is a distribution on RN with N>1 and if ∂jf∈Lj ,σj ∩LN,1 uloc with 1≤pj≤N and σj=1 when pj=1 or N, then f is bounded, continuous and has a finite constant radial limit at infinity. Here, Lp,σ is the classical Lorentz space and L uloc is a “uniformly local” subspace of L loc larger than L p,σ when p<∞. We also show that f∈BUC if, in addition, ∂jf∈Lj ,σj ∩Lquloc with q>N whenever pj<N and that, if so, the limit of f at infinity is uniform if the pj are suitably distributed. Only a few special cases have been considered in the literature, under much more restrictive assumptions that do not involve uniformly local spaces (pj=N and f vanishing at infinity, or ∂jf∈L∩L with p<N<q). Various similar results hold under integrability conditions on the higher order derivatives of f. All of them are applicable to g∗f with g∈L1 and f as above, or under weaker assumptions on f and stronger ones on g. When g is a Bessel kernel, the results are provably optimal in some cases.","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Algebraic cycles and triple $K3$ burgers","authors":"R. Laterveer","doi":"10.4310/ARKIV.2019.V57.N1.A9","DOIUrl":"https://doi.org/10.4310/ARKIV.2019.V57.N1.A9","url":null,"abstract":"We consider surfaces of geometric genus $3$ with the property that their transcendental cohomology splits into $3$ pieces, each piece coming from a $K3$ surface. For certain families of surfaces with this property, we can show there is a similar splitting on the level of Chow groups (and Chow motives).","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Toeplitz operators with piecewise continuous symbols on the Hardy space $H^1$","authors":"S. Miihkinen, J. Virtanen","doi":"10.4310/arkiv.2019.v57.n2.a9","DOIUrl":"https://doi.org/10.4310/arkiv.2019.v57.n2.a9","url":null,"abstract":"The geometric descriptions of the (essential) spectra of Toeplitz operators with piecewise continuous symbols are among the most beautiful results about Toeplitz operators on Hardy spaces $H^p$ with $1<p<infty$. In the Hardy space $H^1$, the essential spectra of Toeplitz operators are known for continuous symbols and symbols in the Douglas algebra $C+H^infty$. It is natural to ask whether the theory for piecewise continuous symbols can also be extended to $H^1$. We answer this question in negative and show in particular that the Toeplitz operator is never bounded on $H^1$ if its symbol has a jump discontinuity.","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the tree structure of orderings and valuations on rings","authors":"Simon Muller","doi":"10.4310/ARKIV.2021.V59.N1.A6","DOIUrl":"https://doi.org/10.4310/ARKIV.2021.V59.N1.A6","url":null,"abstract":"Let $R$ be a not necessarily commutative ring with $1.$ In the present paper we first introduce a notion of quasi-orderings, which axiomatically subsumes all the orderings and valuations on $R$. We proceed by uniformly defining a coarsening relation $leq$ on the set $mathcal{Q}(R)$ of all quasi-orderings on $R.$ One of our main results states that $(mathcal{Q}(R),leq')$ is a rooted tree for some slight modification $leq'$ of $leq,$ i.e. a partially ordered set admitting a maximum such that for any element there is a unique chain to that maximum. As an application of this theorem we obtain that $(mathcal{Q}(R),leq')$ is a spectral set, i.e. order-isomorphic to the spectrum of some commutative ring with $1.$ We conclude this paper by studying $mathcal{Q}(R)$ as a topological space.","PeriodicalId":55569,"journal":{"name":"Arkiv for Matematik","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2018-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}