Journal of the
Korean Mathematical Society
JKMS

ISSN(Print) 0304-9914 ISSN(Online) 2234-3008

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    March, 2024 | Volume 61, No. 2
  • 2024-03-01

    Multiple weighted estimates for multilinear commutators of multilinear singular integrals with generalized kernels

    Liwen Gao, Yan Lin, Shuhui Yang

    Abstract : In this paper, the weighted $L^{p}$ boundedness of multilinear commutators and multilinear iterated commutators generated by the multilinear singular integral operators with generalized kernels and BMO functions is established, where the weight is multiple weight. Our results are generalizations of the corresponding results for multilinear singular integral operators with standard kernels and Dini kernels under certain conditions.

  • 2024-03-01

    Asymptotic behavior of solutions to stochastic 3D globally modified Navier-Stokes equations with unbounded delays

    Cung The Anh, Vu Manh Toi, Phan Thi Tuyet

    Abstract : This paper studies the existence of weak solutions and the stability of stationary solutions to stochastic 3D globally modified Navier-Stokes equations with unbounded delays in the phase space $BCL_{-\infty}(H)$. We first prove the existence and uniqueness of weak solutions by using the classical technique of Galerkin approximations. Then we study stability properties of stationary solutions by using several approach methods. In the case of proportional delays, some sufficient conditions ensuring the polynomial stability in both mean square and almost sure senses will be provided.

  • 2024-03-01

    Stress-energy tensor of the traceless Ricci tensor and Einstein-type manifolds

    Gabjin Yun

    Abstract : In this paper, we introduce the notion of stress-energy tensor $Q$ of the traceless Ricci tensor for Riemannian manifolds $(M^n, g)$, and investigate harmonicity of Riemannian curvature tensor and Weyl curvature tensor when $(M, g)$ satisfies some geometric structure such as critical point equation or vacuum static equation for smooth functions.

  • 2024-03-01

    Remarks on Ulrich bundles of small ranks over quartic fourfolds

    Yeongrak Kim

    Abstract : In this paper, we investigate a few strategies to construct Ulrich bundles of small ranks over smooth fourfolds in $\mathbb{P}^5$, with a focus on the case of special quartic fourfolds. First, we give a necessary condition for Ulrich bundles over a very general quartic fourfold in terms of the rank and the Chern classes. Second, we give an equivalent condition for Pfaffian fourfolds in every degree in terms of arithmetically Gorenstein surfaces therein. Finally, we design a computer-based experiment to look for Ulrich bundles of small rank over special quartic fourfolds via deformation theory. This experiment gives a construction of numerically Ulrich sheaf of rank $4$ over a random quartic fourfold containing a del Pezzo surface of degree $5$.

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  • 2024-03-01

    On the linear independence measures of logarithms of rational numbers. II

    Abderraouf Bouchelaghem, Yuxin He, Yuanhang Li, Qiang Wu

    Abstract : In this paper, we give a general method to compute the linear independence measure of $1, \log(1-1/r),\log(1+1/s)$ for infinitely many integers $r$ and $s$. We also give improvements for the special cases when $r=s$, for example, $\nu(1, \log 3/4, \log 5/4) \leq 9.197$.

  • 2024-03-01

    Real hypersurfaces in the complex hyperbolic quadric with cyclic parallel structure Jacobi operator

    Jin Hong Kim, Hyunjin Lee, Young Jin Suh

    Abstract : Let $M$ be a real hypersurface in the complex hyperbolic quadric~${Q^{m}}^{*}$, $m \geq 3$. The Riemannian curvature tensor field~$R$ of~$M$ allows us to define a symmetric Jacobi operator with respect to the Reeb vector field~$\xi$, which is called the structure Jacobi operator~$R_{\xi} = R(\, \cdot \, , \xi) \xi \in \text{End}(TM)$. On the other hand, in~\cite{Semm03}, Semmelmann showed that the cyclic parallelism is equivalent to the Killing property regarding any symmetric tensor. Motivated by his result above, in this paper we consider the cyclic parallelism of the structure Jacobi operator~$R_{\xi}$ for a real hypersurface~$M$ in the complex hyperbolic quadric~${Q^{m}}^{*}$. Furthermore, we give a complete classification of Hopf real hypersurfaces in ${Q^{m}}^{*}$ with such a property.

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  • 2024-03-01

    A note on Sobolev type trace inequalities for $s$-harmonic extensions

    Yongrui Tang, Shujuan Zhou

    Abstract : In this paper, apply the regularities of the fractional Poisson kernels, we establish the Sobolev type trace inequalities of homogeneous Besov spaces, which are invariant under the conformal transforms. Also, by the aid of the Carleson measure characterizations of Q type spaces, the local version of Sobolev trace inequalities are obtained.

  • 2024-03-01

    Conics in quintic del Pezzo varieties

    Kiryong Chung, Sanghyeon Lee

    Abstract : The smooth quintic del Pezzo variety $Y$ is well-known to be obtained as a linear sections of the Grassmannian variety $\mathrm{Gr}(2,5)$ under the Pl\"ucker embedding into $\mathbb{P}^{9}$. Through a local computation, we show the Hilbert scheme of conics in $Y$ for $\text{dim} Y \ge 3$ can be obtained from a certain Grassmannian bundle by a single blowing-up/down transformation.

  • 2024-03-01

    Positive solutions to discrete harmonic functions in unbounded cylinders

    Fengwen Han, Lidan Wang

    Abstract : In this paper, we study the positive solutions to a discrete harmonic function for a random walk satisfying finite range and ellipticity conditions, killed at the boundary of an unbounded cylinder in $\mathbb{Z}^d$. We first prove the existence and uniqueness of positive solutions, and then establish that all the positive solutions are generated by two special solutions, which are exponential growth at one end and exponential decay at the other. Our method is based on maximum principle and a Harnack type inequality.

  • 2024-03-01

    Shadowing property for ADMM flows

    Yoon Mo Jung , Bomi Shin , Sangwoon Yun

    Abstract : There have been numerous studies on the characteristics of the solutions of ordinary differential equations for optimization methods, including gradient descent methods and alternating direction methods of multipliers. To investigate computer simulation of ODE solutions, we need to trace pseudo-orbits by real orbits and it is called shadowing property in dynamics. In this paper, we demonstrate that the flow induced by the alternating direction methods of multipliers (ADMM) for a $C^2$ strongly convex objective function has the eventual shadowing property. For the converse, we partially answer that convexity with the eventual shadowing property guarantees a unique minimizer. In contrast, we show that the flow generated by a second-order ODE, which is related to the accelerated version of ADMM, does not have the eventual shadowing property.

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March, 2024
Vol.61 No.2

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