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
  • Higher integrability near the initial boundary for nonhomogeneous parabolic systems of 𝑝-Laplacian type
    Forum Math. (IF 0.733) Pub Date : 2020-08-06
    Sun-Sig Byun; Wontae Kim; Minkyu Lim

    We establish a sharp higher integrability near the initial boundary for a weak solution to the following p-Laplacian type system:

    更新日期:2020-09-18
  • Explicit Burgess-like subconvex bounds for GL2 × GL1
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Han Wu

    We make the polynomial dependence on the fixed representation π in our previous subconvex bound of L⁢(12,π⊗χ) for GL2×GL1 explicit, especially in terms of the usual conductor 𝐂⁢(πfin). There is no clue that the original choice, due to Michel and Venkatesh, of the test function at the infinite places should be the optimal one. Hence we also investigate a possible variant of such local choices in some

    更新日期:2020-09-18
  • Generalised Iwasawa invariants and the growth of class numbers
    Forum Math. (IF 0.733) Pub Date : 2020-09-01
    Sören Kleine

    We study the generalised Iwasawa invariants of ℤpd-extensions of a fixed number field K. Based on an inequality between ranks of finitely generated torsion ℤp⁢[[T1,…,Td]]-modules and their corresponding elementary modules, we prove that these invariants are locally maximal with respect to a suitable topology on the set of ℤpd-extensions of K, i.e., that the generalised Iwasawa invariants of a ℤpd-extension

    更新日期:2020-09-18
  • When the image of a derivation on a uniformly complete 𝑓-algebra is contained in the radical
    Forum Math. (IF 0.733) Pub Date : 2020-08-06
    Mohamed Ali Toumi

    In 1977, Colville, Davis, and Keimel [Positive derivations on f-rings, J. Aust. Math. Soc. Ser. A 23 1977, 3, 371–375] proved that a positive derivation on an Archimedean f-algebra A has its range in the set of nilpotent elements of A. The main objective of this paper is to obtain a generalization of the above Colville, Davis and Keimel result to general derivations. Moreover, we give a new version

    更新日期:2020-09-15
  • On rational homotopy and minimal models
    Forum Math. (IF 0.733) Pub Date : 2020-09-09
    Christoph Bock

    We prove a result that enables us to calculate the rational homotopy of a wide class of spaces by the theory of minimal models.

    更新日期:2020-09-10
  • Dyadic bilinear estimates and applications to the well-posedness for the 2D Zakharov–Kuznetsov equation in the endpoint space 𝐻−1/4
    Forum Math. (IF 0.733) Pub Date : 2020-08-06
    Zhaohui Huo; Yueling Jia

    The Cauchy problem of the 2D Zakharov–Kuznetsov equation ∂t⁡u+∂x⁡(∂x⁢x+∂y⁢y)⁡u+u⁢ux=0 is considered. It is shown that the 2D Z-K equation is locally well-posed in the endpoint Sobolev space H-1/4, and it is globally well-posed in H-1/4 with small initial data. In this paper, we mainly establish some new dyadic bilinear estimates to obtain the results, where the main novelty is to parametrize the singularity

    更新日期:2020-09-08
  • Decomposition and classification of length functions
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Dario Spirito

    We study decompositions of length functions on integral domains as sums of length functions constructed from overrings. We find a standard representation when the integral domain admits a Jaffard family, when it is Noetherian and when it is a Prüfer domains such that every ideal has only finitely many minimal primes. We also show that there is a natural bijective correspondence between singular length

    更新日期:2020-09-01
  • Conjugacy classes and automorphisms of twin groups
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Tushar Kanta Naik; Neha Nanda; Mahender Singh

    The twin group Tn is a right-angled Coxeter group generated by n-1 involutions, and the pure twin group PTn is the kernel of the natural surjection from Tn onto the symmetric group on n symbols. In this paper, we investigate some structural aspects of these groups. We derive a formula for the number of conjugacy classes of involutions in Tn, which, quite interestingly, is related to the well-known

    更新日期:2020-09-01
  • Optimal sup norm bounds for newforms on GL2 with maximally ramified central character
    Forum Math. (IF 0.733) Pub Date : 2020-09-01
    Félicien Comtat

    Recently, the problem of bounding the sup norms of L2-normalized cuspidal automorphic newforms ϕ on GL2 in the level aspect has received much attention. However at the moment strong upper bounds are only available if the central character χ of ϕ is not too highly ramified. In this paper, we establish a uniform upper bound in the level aspect for general χ. If the level N is a square, our result reduces

    更新日期:2020-09-01
  • Frontmatter
    Forum Math. (IF 0.733) Pub Date : 2020-09-01

    Journal Name: Forum Mathematicum Volume: 32 Issue: 5 Pages: i-iv

    更新日期:2020-09-01
  • 𝐿𝑝-estimates for rough bi-parameter Fourier integral operators
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Guangqing Wang; Wenyi Chen

    In this paper, we study the Lq-Lr boundedness of bi-parameter Fourier integral operators defined by general rough Hörmander class amplitudes.

    更新日期:2020-08-31
  • Smoothing theorems for Radon transforms over hypersurfaces and related operators
    Forum Math. (IF 0.733) Pub Date : 2020-08-11
    Michael Greenblatt

    We extend the theorems of [M. Greenblatt, Lp Sobolev regularity of averaging operators over hypersurfaces and the Newton polyhedron, J. Funct. Anal. 276 2019, 5, 1510–1527] on Lp to Lsp Sobolev improvement for translation invariant Radon and fractional singular Radon transforms over hypersurfaces, proving Lp to Lsq boundedness results for such operators. Here q≥p but s can be positive, negative, or

    更新日期:2020-08-11
  • Very degenerate elliptic equations under almost critical Sobolev regularity
    Forum Math. (IF 0.733) Pub Date : 2020-08-06
    Albert Clop; Raffaella Giova; Farhad Hatami; Antonia Passarelli di Napoli

    We prove the local Lipschitz continuity and the higher differentiability of local minimizers of functionals of the form

    更新日期:2020-08-06
  • Automorphic Schwarzian equations
    Forum Math. (IF 0.733) Pub Date : 2020-08-06
    Abdellah Sebbar; Hicham Saber

    This paper concerns the study of the Schwartz differential equation {h,τ}=s⁢E4⁡(τ), where E4 is the weight 4 Eisenstein series and s is a complex parameter. In particular, we determine all the values of s for which the solutions h are modular functions for a finite index subgroup of SL2⁡(ℤ). We do so using the theory of equivariant functions on the complex upper-half plane as well as an analysis of

    更新日期:2020-08-06
  • Indefinite Einstein metrics on nice Lie groups
    Forum Math. (IF 0.733) Pub Date : 2020-08-06
    Diego Conti; Federico A. Rossi

    We introduce a systematic method to produce left-invariant, non-Ricci-flat Einstein metrics of indefinite signature on nice nilpotent Lie groups. On a nice nilpotent Lie group, we give a simple algebraic characterization of non-Ricci-flat left-invariant Einstein metrics in both the class of metrics for which the nice basis is orthogonal and a more general class associated to order two permutations

    更新日期:2020-08-06
  • Square function inequality for a class of Fourier integral operators satisfying cinematic curvature conditions
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Chuanwei Gao; Changxing Miao; Jianwei-Urbain Yang

    In this paper, we establish an improved variable coefficient version of the square function inequality, by which the local smoothing estimate Lαp→Lp for the Fourier integral operators satisfying cinematic curvature condition is further improved. In particular, we establish almost sharp results for 2

    更新日期:2020-07-21
  • Homological epimorphisms, homotopy epimorphisms and acyclic maps
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Joseph Chuang; Andrey Lazarev

    We show that the notions of homotopy epimorphism and homological epimorphism in the category of differential graded algebras are equivalent. As an application we obtain a characterization of acyclic maps of topological spaces in terms of induced maps of their chain algebras of based loop spaces. In the case of a universal acyclic map we obtain, for a wide class of spaces, an explicit algebraic description

    更新日期:2020-07-21
  • Summation formulae involving Stirling and Lah numbers
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Dongwei Guo

    By making use of the generating function method, we derive several summation formulae involving Stirling numbers and Lah numbers as well as other classical combinatorial numbers named after Bernoulli, Euler, Bell, Genocchi, Cauchy, Derangement, Harmonic, Fibonacci and Lucas.

    更新日期:2020-07-21
  • Operations that preserve integrability, and truncated Riesz spaces
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Marco Abbadini

    For any real number p∈[1,+∞), we characterise the operations ℝI→ℝ that preserve p-integrability, i.e., the operations under which, for every measure μ, the set ℒp⁢(μ) is closed. We investigate the infinitary variety of algebras whose operations are exactly such functions. It turns out that this variety coincides with the category of Dedekind σ-complete truncated Riesz spaces, where truncation is meant

    更新日期:2020-07-21
  • Variation and oscillation inequalities for commutators in two-weight setting
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Yongming Wen; Weichao Guo; Huoxiong Wu

    This paper studies the two-weight estimates of variation and oscillation operators for commutators of singular integrals with weighted BMO functions. A new characterization of weighted BMO spaces via the boundedness of variation and oscillation operators for the iterated commutators of Calderón–Zygmund singular integrals in the two-weight setting is given.

    更新日期:2020-07-20
  • Convexity of sets in metric Abelian groups
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Włodzimierz Fechner; Zsolt Páles

    In the present paper, we introduce a new concept of convexity which is generated by a family of endomorphisms of an Abelian group. In Abelian groups, equipped with a translation invariant metric, we define the boundedness, the norm, the modulus of injectivity and the spectral radius of endomorphisms. Beyond the investigation of their properties, our first main goal is an extension of the celebrated

    更新日期:2020-07-20
  • Two-weighted inequalities for maximal operators related to Schrödinger differential operator
    Forum Math. (IF 0.733) Pub Date : 2020-07-16
    Maria Amelia Vignatti; Oscar Salinas; Silvia Hartzstein

    We introduce classes of pairs of weights closely related to Schrödinger operators, which allow us to get two-weight boundedness results for the Schrödinger fractional integral and its commutators. The techniques applied in the proofs strongly rely on one hand, boundedness results in the setting of finite measure spaces of homogeneous type and, on the other hand, Fefferman–Stein-type inequalities that

    更新日期:2020-07-20
  • 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
  • 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:2020-06-11
  • 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
  • Instanton bundles on two Fano threefolds of index 1
    Forum Math. (IF 0.733) Pub Date : 2020-05-09
    Gianfranco Casnati; Ozhan Genc

    We deal with instanton bundles on the product ℙ1×ℙ2 and the blow up of ℙ3 along a line. We give an explicit construction leading to instanton bundles. Moreover, we also show that they correspond to smooth points of a unique irreducible component of their moduli space.

    更新日期:2020-05-09
  • The third partial cohomology group and existence of extensions of semilattices of groups by groups
    Forum Math. (IF 0.733) Pub Date : 2020-05-09
    Mikhailo Dokuchaev; Mykola Khrypchenko; Mayumi Makuta

    We introduce the concept of a partial abstract kernel associated to a group G and a semilattice of groups A and relate the partial cohomology group H3⁢(G,C⁢(A)) with the obstructions to the existence of admissible extensions of A by G which realize the given abstract kernel. We also show that if such extensions exist, then they are classified by H2⁢(G,C⁢(A)).

    更新日期:2020-05-09
  • Solvable Lie and Leibniz superalgebras with a given nilradical
    Forum Math. (IF 0.733) Pub Date : 2020-05-09
    Luisa María Camacho; José Manuel Fernández Barroso; Rosa María Navarro

    Throughout this paper we show that under certain conditions the method for describing solvable Leibniz (resp. Lie) algebras with given nilradical by means of non-nilpotent outer derivations of the nilradical is also applicable to the case Leibniz (resp. Lie) superalgebras. Moreover, after having established the general method for Lie and Leibniz superalgebras, we classify all the solvable superalgebras

    更新日期:2020-05-09
  • 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
  • Carleson measure characterizations of the Campanato type space associated with Schrödinger operators on stratified Lie groups
    Forum Math. (IF 0.733) Pub Date : 2020-04-17
    Yixin Wang; Yu Liu; Chuanhong Sun; Pengtao Li

    Let ℒ=-Δ𝔾+V be a Schrödinger operator on the stratified Lie group 𝔾, where Δ𝔾 is the sub-Laplacian and the nonnegative potential V belongs to the reverse Hölder class Bq0 with q0>𝒬/2 and 𝒬 is the homogeneous dimension of 𝔾. In this article, by Campanato type spaces Λℒα⁢(𝔾), we introduce Hardy type spaces associated with ℒ denoted by Hℒp⁢(𝔾) and prove the atomic characterization of Hℒp⁢(𝔾)

    更新日期:2020-04-17
  • 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
Contents have been reproduced by permission of the publishers.
导出
全部期刊列表>>
《自然》编辑与您分享如何成为优质审稿人-信息流
物理学研究前沿热点精选期刊推荐
科研绘图
欢迎报名注册2020量子在线大会
化学领域亟待解决的问题
材料学研究精选新
GIANT
自然职场线上招聘会
ACS ES&T Engineering
ACS ES&T Water
屿渡论文,编辑服务
阿拉丁试剂right
张晓晨
田蕾蕾
李闯创
刘天飞
隐藏1h前已浏览文章
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
天合科研
x-mol收录
X-MOL
清华大学
廖矿标
陈永胜
试剂库存
down
wechat
bug