Researchers Database

Umegaki Ichihara Yumiko

    Faculty Division of Natural Sciences Research Group of Mathematics Associate Professor
Last Updated :2021/10/20

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Research Areas

  • Natural sciences, Algebra

Research Experience

  • 2010, -:奈良女子大学理学部数学科・准教授
  • 2010 - 2010, :広島大学大学院工学研究科情報工学専攻・准教授
  • 2007 - 2010, :広島大学大学院工学研究科情報工学専攻・助教
  • 2003 - 2007, :広島大学大学院工学研究科情報工学専攻・助手
  • 2002 - 2003, :日本学術振興会特別研究員 PD

Education

  • - 2002, Nagoya University, Japan

Published Papers

  • Bicubic number fields with large class numbers

    Yasuko Morita; Atsuki Umegaki; Yumiko Umegaki

    2020, Advanced Studies in Pure Mathematics, 84, 335 - 351

    Scientific journal

  • Quartic fields with large class numbers

    Atsuki Umegaki; Yumiko Umegaki

    2020, Rocky Mountain Journal of Mathematics, 50 (1), 267 - 280, doi

    Scientific journal

  • On the density function for the value-distribution of automorphic L-functions

    Kohji Matsumoto; Yumiko Umegaki

    2019, Journal of Number Theory, 198, 176 - 199, doi

    Scientific journal

  • On the value-distribution of the difference between logarithms of two symmetric power L-functions

    Kohji Matsumoto; Yumiko Umegaki

    Aug. 2018, International Journal of Number Theory, 14/ 07, 2045 - 2081, doi

    Scientific journal

  • The first moment of L-functions of primitive forms on Gamma(0)(p(alpha)) and a basis of old forms

    Yumiko Ichihara

    We consider the first moment of. the value of automorphic L-functions at an arbitrary point on the critical line, a sum over primitive forms weighted by their Petersson's norm. In this paper, we obtain an asymptotic formula for it when weight k is an even integer satisfying 0 < k < 12 or k = 14 and level is p(alpha), where p is a prime number. This formula yields a lower bound of the number of primitive forms, whose L-functions do not vanish at that point. (C) 2010 Elsevier Inc. All rights reserved., ACADEMIC PRESS INC ELSEVIER SCIENCE, Feb. 2011, JOURNAL OF NUMBER THEORY, 131 (2), 343 - 362, doi;web_of_science

    Scientific journal

  • Non-vanishing of the value of L-functions attached to primitive forms at a fixed point on the critical line

    Yumiko Ichihara

    2010, 数理解析研究所講究録, 1710, 29 - 41

  • Estimates of a certain sum involving coefficients of cusp forms in weight and level aspects

    Y. Ichihara

    We consider the sum of coefficients which are in the Dirichlet series expansion of symmetric square L-functions. In this paper, we obtain two estimates of this sum in weight and level aspects. These imply two estimates of the sum of the n(2)th Fourier coefficients of cusp forms., SPRINGER, Jun. 2008, LITHUANIAN MATHEMATICAL JOURNAL, 48 (2), 188 - 202, doi;web_of_science

    Scientific journal

  • On the Siegel-Tatuzawa theorem for a class of L-functions

    Yumiko Ichihara; Kohji Matsumoto

    We consider an effective lower bound of the Siegel-Tatuzawa type for general L-functions with three standard assumptions. We further assume three hypotheses in this paper that are essential in developing our argument. Under these assumptions and hypotheses, we prove a theorem of Siegel-Tatuzawa type for general L-functions. In particular, we prove such a theorem for symmetric power L-functions under certain assumptions., KYUSHU UNIV, FAC MATHEMATICS, Mar. 2008, KYUSHU JOURNAL OF MATHEMATICS, 62 (1), 201 - 215, doi;web_of_science

    Scientific journal

  • Euler 積で定義される L 関数の Siegel-Tatuzawa の定理について

    市原 由美子

    2006, 数理解析研究所講究録, 1511, 74 - 81

  • Hilbert cusp form に付随する L 関数の収束性

    市原 由美子

    2004, 数理解析研究所講究録, 1384, 37 - 41

  • On Riesz mean for the coefficients of twisted Rankin-Selberg L-functions

    Y Ichihara

    Rankin obtained the asymptotic formula for the sum of coefficients of Rankin-Selberg L-series associated with a cusp form and a trivial character. Ivic-Matsumoto-Tanigawa studied the error term in it by using a mean value formula which is yielded from the Voronoi formula of the Riesz mean. In this paper, we consider more general Rankin-Selberg L-series, It is associated with two cusp forms and a non-trivial character mod d. Ivic-Matsumoto-Tanigawa's method cannot be applied directly to our case. We consider the sum of coefficients of twisted Rankin-Selberg L-series by a modification of their method., MATH SOC JAPAN, Jan. 2003, JOURNAL OF THE MATHEMATICAL SOCIETY OF JAPAN, 55 (1), 81 - 100, doi;web_of_science

    Scientific journal

  • The evaluation of the sum over arithmetic progressions for the coefficients of the Rankin-Selberg series

    Yumiko Ichihara

    2003, Japanese Journal of Mathematics, 29 (2), 297 - 314, doi

    Scientific journal

  • Rankin-Selberg L 関数の zero-free region --- Siegel-Tatuzawa 型の定理について ---

    市原 由美子

    2002, 数理解析研究所講究録, 1274, 53 - 61

  • The evaluation of the sum over arithmetic progressions for the coefficients of the Rankin-Selberg series II

    Y Ichihara

    SPRINGER, 2002, ANALYTIC NUMBER THEORY, 6, 173 - 182, doi;web_of_science

    International conference proceedings

  • On Riesz mean for the coefficients of the twisted Rankin-Selberg L-function

    Yumiko Ichihara

    2001, 数理解析研究所講究録, 1219, 235 - 244

  • The evaluation of the sum over arithmetic progressions for the coefficients of the Rankin-Selberg series

    市原 由美子

    2000, 数理解析研究所講究録, 1160, 110 - 118

  • The Siegel-Walfisz theorem for Rankin-Selberg L-functions associated with two cusp forms

    Y Ichihara

    POLISH ACAD SCIENCES INST MATHEMATICS, 2000, ACTA ARITHMETICA, 92 (3), 215 - 227, doi;web_of_science

    Scientific journal

  • 2 つの cusp form の Fourier 係数の積に対する算術級数の素数定理と Rankin-Selberg L 関数の zero-free region

    市原 由美子

    1999, 数理解析研究所講究録, 1091, 27 - 35

  • 2つの cusp form の Fourier 係数の積に対する算術級数の素数定理と Rankin-Selberg L 関数の zero-free region

    市原 由美子

    1998, 中部数理フォーラム, 4, 39 - 50

  • On the value-distribution of symmetric power L-functions

    Kohji Matsumoto; Yumiko Umegaki

    2020, “Topics in Number Theory”, Proceedings of a Conference organized by the Institute of Mathematical Sciences, Chennai and IIT Ropar during 22–25th December, 2017, On the Occasion of the 130th Birth Anniversary of Srinivasa Ramanujan, edited by Tapas Chatterjee and Sanoli Gun, Lecture Notes Series Number 26, 147 - 167

    International conference proceedings

Presentations

  • 類数の大きな 4 次拡大体について

    梅垣 敦紀; 梅垣 由美子

    愛知数論セミナー, 13 Jul. 2019

  • On the value-distribution of the difference between logarithms of two symmetric power L-functions.

    Yumiko Umegaki

    Various Aspects of Multiple Zeta Function, 25 Aug. 2017

  • 保型 L 関数の対数値の平均と密度関数に関する考察

    愛知数論セミナー, 22 Apr. 2017

  • On the value-distribution of the difference between logarithms of two symmetric power L-functions

    RIMS Workshop 2016 Problems and prospects in Analytic Number Theory, 02 Nov. 2016

  • 保型 L 関数の対数値の平均と密度関数

    早稲田整数論セミナー, 31 Jul. 2015

  • Non-vanishing of the automorphic L-functions at the point on the critical line.

    The 15th. Joint Workshop on Number Theory between Japan and Taiwan, 19 Mar. 2010

  • primitive form に対する保型 L 関数の critical line 上の点における first moment

    第 2 回ゼータ若手研究集会, 21 Feb. 2009

  • 保型 L 関数の non-vanishing theorem

    第二回数論女性の集まり, 09 May 2009

  • The first moment of the value of automorphic L-functions over primitive forms on the critical line.

    CONFERENCE IN NUMBER THEORY, 27 Jun. 2009

  • Cusp form に付随する L 関数の 1/2+it における first moment

    日本数学会・代数学分科会, 24 Sep. 2009

  • Non-vanishing of the value of the L-functions attached to primitive forms on the critical line.

    RIMS Workshop 2009 Analytic Number Theory and Related Topics, 14 Oct. 2009

  • Estimates of a certain sum involving coefficients of cusp forms in weight and level aspects.

    French-Japanese Winter School on Zeta and L-functions, 08 Jan. 2008

  • Siegel-Tatuzawa の定理について

    第一回数論女性の集まり, 17 May 2008

  • Siegel-Tatuzawa 型の定理について

    日本数学会・代数学分科会, 28 Mar. 2004

  • On the Siegel-Tatuzawa theorem for a class of L-functions

    RIMS Workshop 2004 Analytic Number Theory and Surrounding Areas, 19 Oct. 2004

  • いくつかの L 関数の係数和の評価について

    整数論シンポジウム, Mar. 2003

  • The convergence of L-functions associated with Hilbert cusp form

    RIMS Workshop 2003 Analytic Number Theory and Surrounding Areas, 29 Sep. 2003

  • Rankin-Selberg L 関数の Siegel zero について

    下関数論小研究集会, Jan. 2002

  • The evaluation of the sum over arithmetic progressions for the coefficients of the Rankin-Selberg series.

    Nishi Waseda Seminar on Number Theory, Sep. 2001

  • Rankin-Selberg L 関数における Siegel-Tatuzawa の定理について

    日本数学会・代数学分科会, 03 Oct. 2001

  • An analogue of the Siegel-Tatuzawa theorem for Rankin-Selberg L-functions

    RIMS Workshop 2001 New Aspects of Analytic Number Theory, 26 Nov. 2001

  • On Riesz mean for the coefficients of the twisted Rankin-Selberg L-functions

    RIMS Workshop 2000 Analytic Number Theory --- Expectations for the 21st Century, 27 Oct. 2000

  • Rankin-Selberg L 関数の係数の和に関する評価について

    日本数学会・代数学分科会, 25 Mar. 1999

  • Rankin-Selberg series の係数 c_n に関する \sum_{n \leq x, n\eqiv a (p)} c_n の評価

    日本数学会・代数学分科会, 28 Sep. 1999

  • The evaluation of the sum over arithmetic progressions for the coefficients of the Rankin-Selberg series.

    RIMS Workshop 1999 Analytic Number Theory and Related Areas, Nov. 1999

  • The Siegel-Walfisz theorem for Rankin-Selberg L-functions associated with two cusp forms

    日本数学会・代数学分科会, 02 Oct. 1998

  • The Siegel-Walfisz Theorem for Rankin-Selberg L-functions associated with two cusp forms.

    RIMS Workshop 1998 Number Theory from the Stand Point of Analytic Number Theory, 19 Oct. 1998

  • old form の空間の基底と保型 L 関数の central point における零の位数について

    大阪大学整数論・保型形式セミナー, 15 Oct. 2010

  • 保型 L 関数の critical line 上の点における non-vanishing について

    整数論シンポジウム(早稲田大学), 19 Mar. 2010

  • Primitive form に付随する L 関数の non-vanishing について

    数論研究会(奈良女子大学), 12 Jan. 2010

  • Primitive form に付随する L 関数の critical line 上の点での non-vanishing について

    早稲田大学整数論セミナー, 20 Nov. 2009

  • On the non-vanishing and order of the zero at 1/2 for L-functions attached to cusp forms

    Summer Number Theory Seminar (Queen's Univ. CANADA), 26 Aug. 2009

  • The first moment of the automorphic L-functions over primitive forms

    西早稲田数論セミナー, 02 Feb. 2009

  • primitive form に対する保型 L 関数の central line 上の点における first moment

    数論セミナー(明治学院大学), 31 Jan. 2009

  • primitive form に付随する L 関数の non-vanishing theorem について

    高知大学数論セミナー, 06 Dec. 2008

  • 保型 L 関数の係数評価 (weight aspect) に関しての Voronoi formula と reflection principle

    解析数論セミナー(名古屋大学), 11 Jul. 2007

  • Euler 積で定義される L 関数の Siegel の零点について

    代数学セミナー(九州大学), 19 Nov. 2004

  • Siegel-Tatuzawa の定理について

    早稲田大学整数論セミナー, 04 Jun. 2004

  • Siegel-Tatuzawa の定理について

    代数学セミナー(広島大学), 12 Dec. 2003

  • The convergence of L-functions associated with Hilbert cusp forms

    整数論セミナー(東京都立大学), 23 Jun. 2003

  • Rankin-Selberg L 関数の zero について

    早稲田大学整数論セミナー, 24 May 2002

  • Rankin-Selberg L 関数に対する Siegel-Tatuzawa の定理について

    整数論・保型形式セミナー(大阪大学), 18 May 2001

  • Rankin-Selberg L 関数における Siegel-Tatuzawa の定理の証明について

    数論セミナー(明治学院大学), 12 May 2001

  • On Riesz mean for the coefficients of the twisted Rankin-Selberg series

    早稲田大学整数論セミナー, 19 Nov. 1999

  • Rankin-Selberg series の係数の合同条件付き部分和の評価について

    数論セミナー(明治学院大学), 24 Apr. 1999

  • The Siegel-Walfisz Theorem for Rankin-Selberg L-functions associated with two cusp forms

    保型形式月例セミナー(東京大学), 17 Oct. 1998

  • The Siegel-Walfisz Theorem for Rankin-Selberg L-functions associated with two cusp forms

    早稲田大学整数論セミナー, 18 Sep. 1998

  • The Siegel-Walfisz Theorem for Rankin-Selberg L-functions associated with two cusp forms

    数論セミナー(明治学院大学), 20 Jun. 1998

Association Memberships

  • 日本数学会



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