当前期刊: Forum Mathematicum Go to current issue    加入关注   
显示样式:        排序: IF: - GO 导出
我的关注
我的收藏
您暂时未登录!
登录
  • Successive coefficients of close-to-convex functions
    Forum Math. (IF 0.733) Pub Date : 2020-06-11
    Paweł Zaprawa

    In this paper we discuss coefficient problems for functions in the class 𝒞0⁢(k). This family is a subset of 𝒞, the class of close-to-convex functions, consisting of functions which are convex in the positive direction of the real axis. Our main aim is to find some bounds of the difference of successive coefficients depending on the fixed second coefficient. Under this assumption we also estimate

    更新日期:2020-07-08
  • Archimedean domains of skew generalized power series
    Forum Math. (IF 0.733) Pub Date : 2020-04-22
    Ryszard Mazurek

    A skew generalized power series ring R⁢[[S,ω,≤]] consists of all functions from a strictly ordered monoid (S,≤) to a ring R whose support is artinian and narrow, with pointwise addition, and with multiplication given by convolution twisted by an action ω of the monoid S on the ring R. Special cases of this ring construction are skew polynomial rings, skew Laurent polynomial rings, skew power series

    更新日期:2020-06-27
  • Rankin–Selberg L-functions via good sections
    Forum Math. (IF 0.733) Pub Date : 2020-05-09
    Yeongseong Jo

    In this article, we revisit Rankin–Selberg integrals established by Jacquet, Piatetski-Shapiro and Shalika. We prove the equality of Rankin–Selberg local factors defined with Schwartz–Bruhat functions and the factors attached to good sections, introduced by Piatetski-Shapiro and Rallis. Moreover, we propose a notion of exceptional poles in the framework of good sections. For cases of Rankin–Selberg

    更新日期:2020-06-27
  • Weyl and Zariski chambers on projective surfaces
    Forum Math. (IF 0.733) Pub Date : 2020-04-22
    Krishna Hanumanthu; Nabanita Ray

    Let X be a nonsingular complex projective surface. The Weyl and Zariski chambers give two interesting decompositions of the big cone of X. Following the ideas of [T. Bauer and M. Funke, Weyl and Zariski chambers on K3 surfaces, Forum Math. 24 2012, 3, 609–625] and [S. A. Rams and T. Szemberg, When are Zariski chambers numerically determined?, Forum Math. 28 2016, 6, 1159–1166], we study these two decompositions

    更新日期:2020-06-27
  • Frontmatter
    Forum Math. (IF 0.733) Pub Date : 2020-07-01

    Journal Name: Forum Mathematicum Volume: 32 Issue: 4 Pages: i-iv

    更新日期:2020-06-27
  • Metrical universality for groups
    Forum Math. (IF 0.733) Pub Date : 2020-06-13
    Michal Doucha

    The aim of this note is to correct the proof of Proposition 2.15 in the original article [M. Doucha, Metrical universality for groups, Forum Math. 29 2017, 4, 847–872].

    更新日期:2020-06-13
  • Frobenius cowreaths and Morita contexts
    Forum Math. (IF 0.733) Pub Date : 2020-06-11
    Daniel Bulacu; Blas Torrecillas

    We prove a uniqueness type theorem for (weak, total) integrals on a Frobenius cowreath in a monoidal category. When the cowreath is, moreover, pre-Galois, we construct a Morita context relating the subalgebra of coinvariants and a certain wreath algebra. Then we see that the strictness of the Morita context is related to the Galois property of the cowreath and the existence of a weak total integral

    更新日期:2020-06-11
  • The non-linear sewing lemma III: Stability and generic properties
    Forum Math. (IF 0.733) Pub Date : 2020-06-11
    Antoine Brault; Antoine Lejay

    Solutions of Rough Differential Equations (RDE) may be defined as paths whose increments are close to an approximation of the associated flow. They are constructed through a discrete scheme using a non-linear sewing lemma. In this article, we show that such solutions also solve a fixed point problem by exhibiting a suitable functional. Convergence then follows from consistency and stability, two notions

    更新日期:2020-06-11
  • On hyperquadrics containing projective varieties
    Forum Math. (IF 0.733) Pub Date : 2020-06-11
    Euisung Park

    Classical Castelnuovo Lemma shows that the number of linearly independent quadratic equations of a nondegenerate irreducible projective variety of codimension c is at most (c+12) and the equality is attained if and only if the variety is of minimal degree. Also G. Fano’s generalization of Castelnuovo Lemma implies that the next case occurs if and only if the variety is a del Pezzo variety. Recently

    更新日期:2020-06-11
  • Characterisation of polyhedral products with finite generalised Postnikov decomposition
    Forum Math. (IF 0.733) Pub Date : 2020-05-19
    Kouyemon Iriye; Daisuke Kishimoto; Ran Levi

    A generalised Postnikov tower for a space X is a tower of principal fibrations with fibres generalised Eilenberg–MacLane spaces, whose inverse limit is weakly homotopy equivalent to X. In this paper we give a characterisation of a polyhedral product ZK⁢(X,A) whose universal cover either admits a generalised Postnikov tower of finite length, or is a homotopy retract of a space admitting such a tower

    更新日期:2020-05-19
  • Irreducible holonomy groups and first integrals for holomorphic foliations
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Victor León; Mitchael Martelo; Bruno Scárdua

    We study groups of germs of complex diffeomorphisms having a property called irreducibility. The notion is motivated by the similar property of the fundamental group of the complement of an irreducible hypersurface in the complex projective space. Natural examples of such groups of germ maps are given by holonomy groups and monodromy groups of integrable systems (foliations) under certain conditions

    更新日期:2020-05-01
  • Strong uncountable cofinality for unitary groups of von Neumann algebras
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Philip A. Dowerk

    We show that unitary groups of II1 factors and of properly infinite von Neumann algebras have uncountable cofinality and the Bergman property. In particular, we obtain a short alternative proof for the strong uncountable cofinality of U⁢(ℓ2⁢(ℕ)), which was first proven by Ricard and Rosendal.

    更新日期:2020-05-01
  • Free division rings of fractions of crossed products of groups with Conradian left-orders
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Joachim Gräter

    Let D be a division ring of fractions of a crossed product F⁢[G,η,α], where F is a skew field and G is a group with Conradian left-order ≤. For D we introduce the notion of freeness with respect to ≤ and show that D is free in this sense if and only if D can canonically be embedded into the endomorphism ring of the right F-vector space F⁢((G)) of all formal power series in G over F with respect to

    更新日期:2020-05-01
  • Well-posedness of backward stochastic partial differential equations with Lyapunov condition
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Wei Liu; Rongchan Zhu

    In this paper we show the existence and uniqueness of strong solutions for a large class of backward SPDEs, where the coefficients satisfy a specific type Lyapunov condition instead of the classical coercivity condition. Moreover, based on the generalized variational framework, we also use the local monotonicity condition to replace the standard monotonicity condition, which is applicable to various

    更新日期:2020-05-01
  • A polynomial bound for the number of maximal systems of imprimitivity of a finite transitive permutation group
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Andrea Lucchini; Mariapia Moscatiello; Pablo Spiga

    We show that there exists a constant a such that, for every subgroup H of a finite group G, the number of maximal subgroups of G containing H is bounded above by a|G:H|3/2. In particular, a transitive permutation group of degree n has at most a⁢n3/2 maximal systems of imprimitivity. When G is soluble, generalizing a classic result of Tim Wall, we prove a much stronger bound, that is, the number of

    更新日期:2020-05-01
  • Spectral properties of certain Moran measures with consecutive and collinear digit sets
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Hai-Hua Wu; Yu-Min Li; Xin-Han Dong

    Let the 2×2 expanding matrix Rk be an integer Jordan matrix, i.e., Rk=diag⁡(rk,sk) or Rk=J⁢(pk), and let Dk={0,1,…,qk-1}⁢v with v=(1,1)T and 2≤qk≤pk,rk,sk for each natural number k. We show that the sequence of Hadamard triples {(Rk,Dk,Ck)} admits a spectrum of the associated Moran measure provided that lim infk→∞⁡2⁢qk⁢∥Rk-1∥<1.

    更新日期:2020-05-01
  • Spectral property of the planar self-affine measures with three-element digit sets
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Ming-Liang Chen; Jing-Cheng Liu; Juan Su

    Let the self-affine measure μM,D be generated by an expanding real matrix M=diag⁡(ρ1-1,ρ2-1) and an integer digit set D={(0,0)t,(α1,α2)t,(β1,β2)t} with α1⁢β2-α2⁢β1≠0. In this paper, the sufficient and necessary conditions for L2⁢(μM,D) to contain an infinite orthogonal set of exponential functions are given.

    更新日期:2020-05-01
  • The Dual Baer Criterion for non-perfect rings
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Jan Trlifaj

    Baer’s Criterion for Injectivity is a useful tool of the theory of modules. Its dual version (DBC) is known to hold for all right perfect rings, but its validity for the non-right perfect ones is a complex problem (first formulated by C. Faith [Algebra. II. Ring Theory, Springer, Berlin, 1976]). Recently, it has turned out that there are two classes of non-right perfect rings: (1) those for which DBC

    更新日期:2020-05-01
  • Varieties of nilpotent Lie superalgebras of dimension ≤ 5
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    María Alejandra Alvarez; Isabel Hernández

    In this paper, we study the varieties of nilpotent Lie superalgebras of dimension ≤5. We provide the algebraic classification of these superalgebras and obtain the irreducible components in every variety. As a byproduct, we construct rigid nilpotent Lie superalgebras of arbitrary dimension.

    更新日期:2020-05-01
  • Smoothness filtration of the magnitude complex
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Kiyonori Gomi

    We introduce an intrinsic filtration to the magnitude chain complex of a metric space, and study basic properties of the associated spectral sequence of the magnitude homology. As an application, the third magnitude homology of the circle is computed.

    更新日期:2020-05-01
  • On the classification of Schreier extensions of monoids with non-abelian kernel
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Nelson Martins-Ferreira; Andrea Montoli; Alex Patchkoria; Manuela Sobral

    We show that any regular (right) Schreier extension of a monoid M by a monoid A induces an abstract kernel Φ:M→End⁡(A)Inn⁡(A). If an abstract kernel factors through SEnd⁡(A)Inn⁡(A), where SEnd⁡(A) is the monoid of surjective endomorphisms of A, then we associate to it an obstruction, which is an element of the third cohomology group of M with coefficients in the abelian group U⁢(Z⁢(A)) of invertible

    更新日期:2020-05-01
  • Newton’s method for nonlinear stochastic wave equations
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Henryk Leszczyński; Monika Wrzosek

    We consider nonlinear stochastic wave equations driven by time-space white noise. The existence of solutions is proved by the method of successive approximations. Next we apply Newton’s method. The main result concerning its first-order convergence is based on Cairoli’s maximal inequalities for two-parameter martingales. Moreover, a second-order convergence in a probabilistic sense is demonstrated

    更新日期:2020-05-01
  • Hörmander type multiplier theorems on bi-parameter anisotropic Hardy spaces
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Liang Huang; Jiao Chen

    The main purpose of this paper is to establish, using the bi-parameter Littlewood–Paley–Stein theory (in particular, the bi-parameter Littlewood–Paley–Stein square functions), a Calderón–Torchinsky type theorem for the following Fourier multipliers on anisotropic product Hardy spaces Hp⁢(ℝn1×ℝn2;A→) (0

    更新日期:2020-05-01
  • On the group of a rational maximal bifix code
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Jorge Almeida; Alfredo Costa; Revekka Kyriakoglou; Dominique Perrin

    We give necessary and sufficient conditions for the group of a rational maximal bifix code Z to be isomorphic with the F-group of Z∩F, when F is recurrent and Z∩F is rational. The case where F is uniformly recurrent, which is known to imply the finiteness of Z∩F, receives special attention. The proofs are done by exploring the connections with the structure of the free profinite monoid over the alphabet

    更新日期:2020-05-01
  • Approximating pointwise products of quasimodes
    Forum Math. (IF 0.733) Pub Date : 2020-05-01
    Mei Ling Jin

    We obtain approximation bounds for products of quasimodes for the Laplace–Beltrami operator on compact Riemannian manifolds of all dimensions without boundary. We approximate the products of quasimodes uv by a low-degree vector space Bn, and we prove that the size of the space dim⁡(Bn) is small. In this paper, we first study bilinear quasimode estimates of all dimensions d=2,3, d=4,5 and d≥6, respectively

    更新日期:2020-05-01
  • Frontmatter
    Forum Math. (IF 0.733) Pub Date : 2020-05-01

    Journal Name: Forum Mathematicum Volume: 32 Issue: 3 Pages: i-iv

    更新日期:2020-05-01
  • Alvis–Curtis duality for representations of reductive groups with Frobenius maps
    Forum Math. (IF 0.733) Pub Date : 2020-04-22
    Junbin Dong

    We generalize the Alvis–Curtis duality to the abstract representations of reductive groups with Frobenius maps. Similar to the case of representations of finite reductive groups, we show that the Alvis–Curtis duality of infinite type, which we define in this paper, also interchanges the irreducible representations in the principal representation category.

    更新日期:2020-04-22
  • Bilinear forms on non-homogeneous Sobolev spaces
    Forum Math. (IF 0.733) Pub Date : 2020-04-15
    Carme Cascante; Joaquín M. Ortega

    In this paper, we show that if b∈L2⁢(ℝn), then the bilinear form defined on the product of the non-homogeneous Sobolev spaces Hs2⁢(ℝn)×Hs2⁢(ℝn), 0

    更新日期:2020-04-15
  • Long time behavior of solutions to 3D generalized MHD equations
    Forum Math. (IF 0.733) Pub Date : 2020-04-15
    Xiaopeng Zhao

    In this paper, we consider the long time behavior of solutions for 3D incompressible MHD equations with fractional Laplacian. Firstly, in a periodic bounded domain, we prove the existence of a global attractor. The analysis reveals a relation between the Laplacian exponent and the regularity of the spaces of velocity and magnetic fields. Finally, in the whole space ℝ3, we establish the sharp algebraic

    更新日期:2020-04-15
  • Boundedness of multi-parameter pseudo-differential operators on multi-parameter local Hardy spaces
    Forum Math. (IF 0.733) Pub Date : 2020-04-15
    Jiao Chen; Wei Ding; Guozhen Lu

    After the celebrated work of L. Hörmander on the one-parameter pseudo-differential operators, the applications of pseudo-differential operators have played an important role in partial differential equations, geometric analysis, harmonic analysis, theory of several complex variables and other branches of modern analysis. For instance, they are used to construct parametrices and establish the regularity

    更新日期:2020-04-15
  • The Kobayashi–Royden metric on punctured spheres
    Forum Math. (IF 0.733) Pub Date : 2020-03-20
    Gunhee Cho; Junqing Qian

    This paper gives an explicit formula of the asymptotic expansion of the Kobayashi–Royden metric on the punctured sphere ℂ⁢ℙ1∖{0,1,∞} in terms of the exponential Bell polynomials. We prove a local quantitative version of the Little Picard’s Theorem as an application of the asymptotic expansion. Furthermore, the approach in the paper leads to the interesting consequence that the coefficients in the asymptotic

    更新日期:2020-03-20
  • Degree bounds for modular covariants
    Forum Math. (IF 0.733) Pub Date : 2020-03-20
    Jonathan Elmer; Müfit Sezer

    Let V,W be representations of a cyclic group G of prime order p over a field 𝕜 of characteristic p. The module of covariants 𝕜⁢[V,W]G is the set of G-equivariant polynomial maps V→W, and is a module over 𝕜⁢[V]G. We give a formula for the Noether bound β⁢(𝕜⁢[V,W]G,𝕜⁢[V]G), i.e. the minimal degree d such that 𝕜⁢[V,W]G is generated over 𝕜⁢[V]G by elements of degree at most d.

    更新日期:2020-03-20
  • Weighted sum formulas of multiple t-values with even arguments
    Forum Math. (IF 0.733) Pub Date : 2020-03-19
    Zhonghua Li; Ce Xu

    In this paper, we study the weighted sums of multiple t-values and of multiple t-star values at even arguments. Some general weighted sum formulas are given, where the weight coefficients are given by (symmetric) polynomials of the arguments.

    更新日期:2020-03-19
  • Unitary representations with Dirac cohomology: A finiteness result for complex Lie groups
    Forum Math. (IF 0.733) Pub Date : 2020-03-19
    Jian Ding; Chao-Ping Dong

    Let G be a connected complex simple Lie group, and let G^d be the set of all equivalence classes of irreducible unitary representations with non-vanishing Dirac cohomology. We show that G^d consists of two parts: finitely many scattered representations, and finitely many strings of representations. Moreover, the strings of G^d come from L^d via cohomological induction and they are all in the good range

    更新日期:2020-03-19
  • Artin L-functions of almost monomial Galois groups
    Forum Math. (IF 0.733) Pub Date : 2020-03-10
    Mircea Cimpoeaş; Florin Nicolae

    If K/ℚ is a finite Galois extension with an almost monomial Galois group and if s0∈ℂ∖{1} is not a common zero for any two Artin L-functions associated to distinct complex irreducible characters of the Galois group, then all Artin L-functions of K/ℚ are holomorphic at s0. We present examples and basic properties of almost monomial groups.

    更新日期:2020-03-10
  • Decomposition rank of approximately subhomogeneous C*-algebras
    Forum Math. (IF 0.733) Pub Date : 2020-03-10
    George A. Elliott; Zhuang Niu; Luis Santiago; Aaron Tikuisis

    It is shown that every Jiang–Su stable approximately subhomogeneous C*-algebra has finite decomposition rank. This settles a key direction of the Toms–Winter conjecture for simple approximately subhomogeneous C*-algebras. A key step in the proof is that subhomogeneous C*-algebras are locally approximated by a certain class of more tractable subhomogeneous algebras, namely a non-commutative generalization

    更新日期:2020-03-10
  • Classification of indecomposable involutive set-theoretic solutions to the Yang–Baxter equation
    Forum Math. (IF 0.733) Pub Date : 2020-02-22
    Wolfgang Rump

    Using the theory of cycle sets and braces, non-degenerate indecomposable involutive set-theoretic solutions to the Yang–Baxter equation are classified in terms of their universal coverings and their fundamental group. The universal coverings are characterized as braces with an adjoint orbit generating the additive group. Using this description, all coverings of non-degenerate indecomposable cycle sets

    更新日期:2020-02-22
  • Alexandroff topologies and monoid actions
    Forum Math. (IF 0.733) Pub Date : 2020-02-22
    Giampiero Chiaselotti; Federico G. Infusino

    Given a monoid S acting (on the left) on a set X, all the subsets of X which are invariant with respect to such an action constitute the family of the closed subsets of an Alexandroff topology on X. Conversely, we prove that any Alexandroff topology may be obtained through a monoid action. Based on such a link between monoid actions and Alexandroff topologies, we firstly establish several topological

    更新日期:2020-02-22
  • Envelopes of circles and spacelike curves in the Lorentz–Minkowski 3-space
    Forum Math. (IF 0.733) Pub Date : 2020-02-11
    Rui Pacheco; Susana D. Santos

    The isotropy projection establishes a correspondence between curves in the Lorentz–Minkowski space 𝐄13 and families of cycles in the Euclidean plane (i.e., curves in the Laguerre plane ℒ2). In this paper, we shall give necessary and sufficient conditions for two given families of cycles to be related by a (extended) Laguerre transformation in terms of the well known Lorentzian invariants for smooth

    更新日期:2020-02-11
Contents have been reproduced by permission of the publishers.
导出
全部期刊列表>>
材料学研究精选
Springer Nature Live 产业与创新线上学术论坛
胸腔和胸部成像专题
自然科研论文编辑服务
ACS ES&T Engineering
ACS ES&T Water
屿渡论文,编辑服务
杨超勇
周一歌
华东师范大学
南京工业大学
清华大学
中科大
唐勇
跟Nature、Science文章学绘图
隐藏1h前已浏览文章
中洪博元
课题组网站
新版X-MOL期刊搜索和高级搜索功能介绍
ACS材料视界
x-mol收录
福州大学
南京大学
王杰
左智伟
湖南大学
清华大学
吴杰
赵延川
中山大学化学工程与技术学院
试剂库存
天合科研
down
wechat
bug