Kodai Mathematical Journal
Online ISSN : 1881-5472
Print ISSN : 0386-5991
ISSN-L : 0386-5991
Current issue
Displaying 1-7 of 7 articles from this issue
  • Yuntao Huang, Weiling Song, Xi Tang
    2025 Volume 48 Issue 1 Pages 1-10
    Published: 2025
    Released on J-STAGE: March 12, 2025
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    Let R be a Gorenstein artin algebra, and let U be a fixed left R-module and k ⩾ 0. When U is Gorenstein injective, if the U-codominant dimension of any injective left R-module is at most k + 1, then the U-dominant dimension of any projective left R-module is at most k + 1. Dually, when U is Gorenstein projective, if the U-dominant dimension of any projective left R-module is at most k + 1, then the U-codominant dimension of any injective left R-module is at most k + 1.

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  • Ya-Nan Li, Zhaoyong Huang
    2025 Volume 48 Issue 1 Pages 11-33
    Published: 2025
    Released on J-STAGE: March 12, 2025
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    Let R and S be rings and RCS a semidualizing bimodule, and let be a subcategory of the Auslander class and . Then for any left R-module M, the -projective dimension of HomR (C,M) is at most the -projective dimension of M, and they are identical when M is in the Bass class . If RCS is faithful and is resolving, then in a short exact sequence of left R-modules, the -projective dimensions of any two terms can determine an upper bound of that of the third term. Furthermore, we apply these results to the cases of being the subcategories of (weak) flat modules, projective modules and respectively. Some known results are obtained as corollaries.

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  • Dong Yeol Oh
    2025 Volume 48 Issue 1 Pages 34-51
    Published: 2025
    Released on J-STAGE: March 12, 2025
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    Let k be an even integer and fSk0(N)) be a newform of weight k. We prove that for each integer N ≥ 16 and for kkN (depending on N), all of nonzero zeros of the odd period polynomial associated to the newform f are on the circle |z| = 1 / √N. For each integer 3 ≤ N ≤ 15, we also investigate the location of the zeros of the odd period polynomial associated to the newform f.

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  • Hiroshi Sawai
    2025 Volume 48 Issue 1 Pages 52-71
    Published: 2025
    Released on J-STAGE: March 12, 2025
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    Kodaira-Thurston manifold is a compact nilmanifold, and it has a Vaisman structure. The purpose in this paper is to calculate the sectional curvature and the Ricci tensor on Kodaira-Thurston manifold. Moreover, we consider curvatures and the Ricci tensor on a compact Vaisman solvmanifold.

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  • Ngô Thị Ngoan, Nguyên Quôc Thăng
    2025 Volume 48 Issue 1 Pages 72-100
    Published: 2025
    Released on J-STAGE: March 12, 2025
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    We consider certain local-global principles related with the isotropy and some splitting problems for connected linear algebraic groups over global fields. The main tools are certain reciprocity law for Tits indices of almost simple groups due to Prasad and Rapinchuk, Harder's Hasse principle for homogeneous projective spaces of reductive groups for number fields and their extensions to global function fields.

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  • Tomoki Fujii, Naoyuki Koike
    2025 Volume 48 Issue 1 Pages 101-122
    Published: 2025
    Released on J-STAGE: March 12, 2025
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    In this paper, we consider translators (for the mean curvature flow) given by a graph of a function on a symmetric space G/K of compact type which is invariant under a hyperpolar action on G/K. First, in the case of G/K = SO(n + 1)/SO(n), SU(n + 1)/S(U(1) × U(n)), Sp(n + 1)/(Sp(1) × Sp(n)) or F4/Spin(9), we classify the shapes of translators in G/K × given by the graphs of functions on G/K which are invariant under the isotropy action KG/K. Next, in the case where G/K is of higher rank, we investigate translators in G/K × given by the graphs of functions on G/K which are invariant under a hyperpolar action HG/K of cohomogeneity two.

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  • Yoonweon Lee
    2025 Volume 48 Issue 1 Pages 123-144
    Published: 2025
    Released on J-STAGE: March 12, 2025
    JOURNAL RESTRICTED ACCESS

    We use the BFK-gluing formula for zeta-determinants to compute the zeta-determinant and analytic torsion of a metric mapping torus induced from an isometry. As applications, we compute the zeta-determinants of the Laplacians defined on a Klein bottle K and some compact co-Kähler manifold Tφ. We also show that a metric mapping torus and a Riemannian product manifold with a round circle have the same heat trace asymptotic expansions. We finally compute the analytic torsion of a metric mapping torus for the Witten deformed Laplacian and recover the result of J. Marcsik in [16].

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