{"title":"A family of reflexive vector bundles of reduction number one","authors":"Cleto B. Miranda-Neto","doi":"10.7146/MATH.SCAND.A-111889","DOIUrl":"https://doi.org/10.7146/MATH.SCAND.A-111889","url":null,"abstract":"A difficult issue in modern commutative algebra asks for examples of modules (more interestingly, reflexive vector bundles) having prescribed reduction number $rgeq 1$. The problem is even subtler if in addition we are interested in good properties for the Rees algebra. In this note we consider the case $r=1$. Precisely, we show that the module of logarithmic vector fields of the Fermat divisor of any degree in projective $3$-space is a reflexive vector bundle of reduction number $1$ and Gorenstein Rees ring.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48536467","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":"The attainment set of the $varphi$-envelope and genericity properties","authors":"A. Cabot, A. Jourani, L. Thibault, D. Zagrodny","doi":"10.7146/MATH.SCAND.A-110766","DOIUrl":"https://doi.org/10.7146/MATH.SCAND.A-110766","url":null,"abstract":"The attainment set of the $varphi$-envelope of a function at a given point is investigated. The inclusion of the attainment set of the $varphi$-envelope of the closed convex hull of a function into the attainment set of the function is preserved in sufficiently general settings to encompass the case $varphi$ being a norm in a power not less than $1$. The non-emptiness of the attainment set is guaranteed on generic subsets of a given space, in several fundamental cases.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49490852","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":"Symmetric approximation sequences, Beilinson-Green algebras and derived equivalences","authors":"Shengyong Pan","doi":"10.7146/math.scand.a-133541","DOIUrl":"https://doi.org/10.7146/math.scand.a-133541","url":null,"abstract":"In this paper, we will consider a class of locally $Phi$-Beilinson-Green algebras, where $Phi$ is an infinite admissible set of the integers, and show that symmetric approximation sequences in $n$-exangulated categories give rise to derived equivalences between quotient algebras of locally $Phi$-Beilinson-Green algebras in the principal diagonals modulo some factorizable ghost and coghost ideals by the locally finite tilting family. Then we get a class of derived equivalent algebras that have not been obtained by using previous techniques. From higher exact sequences, we obtain derived equivalences between subalgebras of endomorphism algebras by constructing tilting complexes, which generalizes Chen and Xi's result for exact sequences. From a given derived equivalence, we get derived equivalences between locally $Phi$-Beilinson-Green algebras of semi-Gorenstein modules. Finally, from given graded derived equivalences of group graded algebras, we get derived equivalences between associated Beilinson-Green algebras of group graded algebras.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47185906","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":"Cohen-Macaulay homological dimensions","authors":"P. Sahandi, Tirdad Sharif, S. Yassemi","doi":"10.7146/math.scand.a-119382","DOIUrl":"https://doi.org/10.7146/math.scand.a-119382","url":null,"abstract":"We introduce new homological dimensions, namely the Cohen-Macaulay projective, injective and flat dimensions for homologically bounded complexes. Among other things we show that (a) these invariants characterize the Cohen-Macaulay property for local rings, (b) Cohen-Macaulay flat dimension fits between the Gorenstein flat dimension and the large restricted flat dimension, and (c) Cohen-Macaulay injective dimension fits between the Gorenstein injective dimension and the Chouinard invariant.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41625570","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":"A revised augmented Cuntz semigroup","authors":"L. Robert, Luis Santiago","doi":"10.7146/MATH.SCAND.A-121016","DOIUrl":"https://doi.org/10.7146/MATH.SCAND.A-121016","url":null,"abstract":"We revise the construction of the augmented Cuntz semigroup functor used by the first author to classify inductive limits of $1$-dimensional noncommutative CW complexes. The original construction has good functorial properties when restricted to the class of C*-algebras of stable rank one. The construction proposed here has good properties for all C*-algebras: we show that the augmented Cuntz semigroup is a stable, continuous, split exact functor, from the category of C*-algebras to the category of Cu-semigroups.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47024793","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":"The reproducing kernel of $mathcal H^2$ and radial eigenfunctions of the hyperbolic Laplacian","authors":"M. Stoll","doi":"10.7146/MATH.SCAND.A-109674","DOIUrl":"https://doi.org/10.7146/MATH.SCAND.A-109674","url":null,"abstract":"In the paper we characterize the reproducing kernel $mathcal {K}_{n,h}$ for the Hardy space $mathcal {H}^2$ of hyperbolic harmonic functions on the unit ball $mathbb {B}$ in $mathbb {R}^n$. Specifically we prove that [ mathcal {K}_{n,h}(x,y) = sum _{alpha =0}^infty S_{n,alpha }(lvert xrvert )S_{n,alpha }(lvert yrvert ) Z_alpha (x,y), ] where the series converges absolutely and uniformly on $Ktimes mathbb {B}$ for every compact subset $K$ of $mathbb {B}$. In the above, $S_{n,alpha }$ is a hypergeometric function and $Z_alpha $ is the reproducing kernel of the space of spherical harmonics of degree α. In the paper we prove that [ 0le mathcal K_{n,h}(x,y) le frac {C_n}{(1-2langle x,yrangle + lvert x rvert^2 lvert y rvert^2)^{n-1}}, ] where $C_n$ is a constant depending only on $n$. It is known that the diagonal function $mathcal K_{n,h}(x,x)$ is a radial eigenfunction of the hyperbolic Laplacian $varDelta_h $ on $mathbb{B} $ with eigenvalue $lambda _2 = 8(n-1)^2$. The result for $n=4$ provides motivation that leads to an explicit characterization of all radial eigenfunctions of $varDelta_h $ on $mathbb{B} $. Specifically, if $g$ is a radial eigenfunction of $varDelta_h $ with eigenvalue $lambda _alpha = 4(n-1)^2alpha (alpha -1)$, then [ g(r) = g(0) frac {p_{n,alpha }(r^2)}{(1-r^2)^{(alpha -1)(n-1)}}, ] where $p_{n,alpha }$ is again a hypergeometric function. If α is an integer, then $p_{n,alpha }(r^2)$ is a polynomial of degree $2(alpha -1)(n-1)$.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47396391","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":"Blow-ups and Fano manifolds of large pseudoindex","authors":"C. Novelli","doi":"10.7146/MATH.SCAND.A-109996","DOIUrl":"https://doi.org/10.7146/MATH.SCAND.A-109996","url":null,"abstract":"We describe the Kleiman-Mori cones of Fano manifolds of large pseudoindex that admit a structure of smooth blow-up.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48322631","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":"Multilinear square functions and multiple weights","authors":"L. Grafakos, P. Mohanty, Saurabh Shrivastava","doi":"10.7146/MATH.SCAND.A-105504","DOIUrl":"https://doi.org/10.7146/MATH.SCAND.A-105504","url":null,"abstract":"In this paper we prove weighted estimates for a class of smooth multilinear square functions with respect to multilinear $A_{vec P}$ weights. In particular, we establish weighted estimates for the smooth multilinear square functions associated with disjoint cubes of equivalent side-lengths. As a consequence, for this particular class of multilinear square functions, we provide an affirmative answer to a question raised by Benea and Bernicot (Forum Math. Sigma 4, 2016, e26) about unweighted estimates for smooth bilinear square functions.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48703267","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":"Remarks on Diophantine approximation in function fields","authors":"Arijit Ganguly, Anish Ghosh","doi":"10.7146/MATH.SCAND.A-109985","DOIUrl":"https://doi.org/10.7146/MATH.SCAND.A-109985","url":null,"abstract":"We study some problems in metric Diophantine approximation over local fields of positive characteristic.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2018-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41981442","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":"The Dirichlet problem for $m$-subharmonic functions on compact sets","authors":"P. Åhag, R. Czyż, Lisa Hed","doi":"10.7146/math.scand.a-119708","DOIUrl":"https://doi.org/10.7146/math.scand.a-119708","url":null,"abstract":"We characterize those compact sets for which the Dirichlet problem has a solution within the class of continuous $m$-subharmonic functions defined on a compact set, and then within the class of $m$-harmonic functions.","PeriodicalId":49873,"journal":{"name":"Mathematica Scandinavica","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2018-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47249935","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}