2025-04-30 2025, Volume 46 Issue 2

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  • Miaoxin Lei , Ruiwei Xu , Peibiao Zhao

    Cheng-Hu-Moruz (2017) completely classified the locally strongly convex centroaffine hypersurfaces with parallel cubic form based on the Calabi product (called the type I Calabi product for short) proposed by Li-Wang (1991).

    In the present paper, the authors introduce the type II Calabi product (in case λ1 = 2λ2), complementing the type I Calabi product (in case λ1 ≠ 2λ2), and achieve a classification of the locally strongly convex centroaffine hypersurfaces in ℝn+1 with vanishing centroaffine shape operator and Weyl curvature tensor by virtue of the types I and II Calabi product.

    As a corollary, 3-dimensional complete locally strongly convex centroaffine hypersurfaces with vanishing centroaffine shape operator are completely classified, which positively answers the centroaffine Bernstein problems III and V by Li-Li-Simon (2004).

  • Vando Narciso , Fatma Ekinci , Erhan Pişkin

    The results of this work deal with the existence and blow up of solutions for the following damped extensible beam with degenerate nonlocal damping and source term $u_{tt}+\Delta^{2}u-M(\Vert\nabla u \Vert^{2})\Delta u+\Vert \Delta u\Vert^{2\alpha}\vert u_{t}\vert^{\gamma}u_{t}=\vert u\vert^{\rho}u$. It is regarded as the second part of the paper by Narciso et al. (in 2023), where global existence, uniqueness and asymptotic stability of strong solutions were obtained for regular initial data in the case ∣uρu ≡ 0.

  • Xianjie Yan , Dachun Yang

    Let

    (X,d,μ)
    be a space of homogeneous type, in the sense of Coifman and Weiss, and
    φ:X×[0,)[0,)
    satisfy that, for almost every
    xX,φ(x,)
    is an Orlicz function and that φ(·, t) is a Muckenhoupt
    A(X)
    weight uniformly in t ∈ [0, ∞). In this article, the authors first establish a new molecular characterization, associated with admissible sequences of balls on
    X
    , of the Musielak-Orlicz Hardy space
    Hφ(X)
    . As an application, the authors also obtain the boundedness of Calderón-Zygmund operators from
    Hφ(X)
    to
    Hφ(X)
    or to the Musielak-Orlicz space
    Lφ(X)
    . The main novelty of these results is that, in the proof of the boundedness of Calderón-Zygmund operators on
    Hφ(X)
    , the authors get rid of the dependence on the reverse doubling property of μ by using this new molecular characterization of
    Hφ(X)
    .

  • Cuifang Sun

    For any positive integer m, let ℤm be the additive group of residue classes modulo m. For A ⊆ ℤm and

    n¯Zm
    , let the representation function
    RA(n¯)
    denote the number of solutions of the equation
    n¯=a¯+a¯
    with unordered pairs
    (a¯,a¯)A×A
    . Let m = 2αM > 2, where α is a positive integer and M is a positive odd integer. In this paper, the author proves that if M ≥ 3, then there exist two distinct sets A, B ⊆ ℤm with ∣AB∣ = m − 2, AB = ∅ and
    Bm¯2+A
    such that
    RA(n¯)=RB(n¯)
    for all
    n¯Zm
    . The author also proves that if M = 1 and A, B ⊆ ℤm with ∣AB∣ = m − 2 and AB = ∅, then
    RA(n¯)=RB(n¯)
    for all
    n¯Zm
    if and only if
    B=m¯2+A
    .

  • Chung Pang Mok , Huimin Zheng

    The authors carry out numerical experiments with regard to the Monte Carlo integration method, using as input the pseudorandom vectors that are generated by the algorithm proposed in [Mok, C. P., Pseudorandom Vector Generation Using Elliptic Curves and Applications to Wiener Processes, Finite Fields and Their Applications, 85, 2023, 102129], which is based on the arithmetic theory of elliptic curves over finite fields. They consider integration in the following two cases: The case of Lebesgue measure on the unit hypercube [0, 1]d, and as well as the case of Wiener measure. In the case of Wiener measure, the construction gives discrete time simulation of an independent sequence of standard Wiener processes, which is then used for the numerical evaluation of Feynman-Kac formulas.

  • Kalyan Chakraborty , Azizul Hoque

    The authors exhibit some new families of cyclotomic fields which have non-trivial plus parts of their class numbers. They also prove the 3-divisibility of the plus part of the class number of another family consisting of infinitely many cyclotomic fields. At the end, they provide some numerical examples supporting our results.

  • Shaoqiang Shang

    In this paper, the author proves that if the dual X* of X is weakly locally uniformly convex and the convex function f is continuous on X, then there exist two sequences

    {fn}n=1
    and
    {gn}n=1
    of continuous functions on X** such that (1) fn(x) ≤ fn+1(x) ≤ f(x) ≤ gn+1(x) ≤ gn(x) whenever xX; (2) the two convex functions fn and gn are Gâteaux differentiable on X; (3) fnf and gnf uniformly on X. Moreover, if the function f is coercive on X, then (1) fn and gn are two w*-lower semicontinuous convex functions on X*; (2)
    epifn=epifn(X×R)¯w
    and
    epign=epign(X×R)¯w
    .

  • Xiaxia Guan , Weihua Yang

    A book embedding of a graph G is a placement of its vertices along the spine of a book, and an assignment of its edges to the pages such that no two edges on the same page cross. The pagenumber of a graph is the minimum number of pages in which it can be embedded. Determining the pagenumber of a graph is NP-hard. A graph is said to be 1-planar if it can be drawn in the plane so that each edge is crossed at most once. The anthors prove that the pagenumber of 1-planar graphs is at most 10.

  • Zhenzhen Feng , Jing Ma

    In this paper, the authors investigate exceptional sets in the Waring-Goldbach problem for unlike powers. For example, estimates are obtained for sufficiently large integers below a parameter subject to the necessary local conditions that do not have a representation as the sum of a square of prime, a cube of prime and a sixth power of prime and a k-th power of prime. These results improve the recent result due to Brüdern in the order of magnitude. Furthermore, the method can be also applied to the similar estimates for the exceptional sets for Waring-Goldbach problem for unlike powers.