Updated on 2025/04/09

写真a

 
SHODA,Toshihiro
 
Organization
Faculty of Engineering Science Professor
Title
Professor
Profile
1998年3月東京理科大学理学部一部数学科卒業。 2000年3月東京工業大学理工学研究科数学専攻修士課程修了。修士(理学)。 2004年3月同博士課程修了。博士(理学)。 2004年4月東京工業大学理工学研究科数学専攻研究支援者。 2005年4月学術振興会特別研究員(PD、九州大学)。 2006年4月佐賀大学文化教育学部講師。 2009年10月同准教授。 2016年4月学部改組により佐賀大学教育学部准教授。 2021年4月関西大学システム理工学部教授。 研究内容は、石鹸膜の数学的モデルになる曲面の幾何的量を特定することにより、その曲面の構造を幾何解析的に解明することを主とする。
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Research Interests

  • Stability of minimal surface

  • Morse index, nullity, signature

  • Minimal surfaces

Research Areas

  • Natural Science / Geometry

Education

  • 東京工業大学   理工学研究科   数学専攻(博士課程)

    2000.4 - 2004.3

  • 東京工業大学   理工学研究科   数学専攻(修士課程)

    1998.4 - 2000.3

  • Tokyo University of Science   Faculty of Science, Division 1   Mathematics

    1994.4 - 1998.3

  • 千葉県立 小金高等学校

    1991.4 - 1994.3

Research History

  • Kansai University   Faculty of Engineering Science   Professor

    2021.4

  • Saga University   Associate Professor

    2016.4 - 2021.3

  • Saga University   Faculty of Culture and Education   Associate Professor

    2009.10 - 2016.3

  • Saga University   Faculty of Culture and Education   Lecturer

    2006.4 - 2009.9

  • 日本学術振興会 特別研究員PD(九州大学)

    2005.4 - 2006.3

  • 東京工業大学大学院 理工学研究科 数学専攻 研究支援者

    2004.4 - 2005.3

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Professional Memberships

  • Mathematical Society of Japan

Papers

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Books

  • Differential Geometry and Tanaka Theory — Differential System and Hypersurface Theory —, Advanced Studies in Pure Mathematics, Volume 82

    Toshihiro Shoda, Kazuhiro Shibuya

    Mathematical Society of Japan  2019.11  ( ISBN:9784864970846

  • 集合・位相に親しむ

    庄田, 敏宏

    現代数学社  2010.4  ( ISBN:9784768704110

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    Total pages:175p   Language:Japanese  

    CiNii Books

MISC

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Research Projects

  • 高種数および高余次元の周期的な極小曲面における幾何的量の研究

    Grant number:24K06750  2024.4 - 2028.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    庄田 敏宏

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    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

  • Laplacian-eigenvalue maximization and minimal surface

    Grant number:23K22393  2022.4 - 2027.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

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    Grant amount:\15990000 ( Direct Cost: \12300000 、 Indirect Cost:\3690000 )

  • 高種数テイト曲線の周期の理論とベクトル値タイヒミュラー保型形式の数論

    Grant number:20K03516  2020.4 - 2025.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    市川 尚志, 庄田 敏宏, 中村 健太郎

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    Grant amount:\4420000 ( Direct Cost: \3400000 、 Indirect Cost:\1020000 )

    テイト曲線とは、有理整数を係数にもつ巾級数環上で定義された楕円曲線の族であり、数論幾何のさまざまな分野で応用されている。研究代表者はこれまでの研究において、テイト曲線の高種数化である「高種数テイト曲線」を構成し、その座標環上での展開を用いて、タイヒミュラー空間上の保型形式「タイヒミュラー保型形式」の理論を構成していた。本研究においては、高種数テイト曲線の周期積分とタイヒミュラー保型形式の理論を、互いに関連づけながら発展させ、物理学や工学への応用も含む次の成果を得た。
    1.高種数テイト曲線上のアーベル微分・積分として「普遍アーベル微分・積分」の明示公式を導き、その応用として、今までリーマン面の退化族に対し解析的な方法によって得られていたアーベル微分・積分の漸近公式を、数論幾何的な方法を用いることによりマンフォード曲線も対象に含んだ形で拡張した。ソリトン解を持つ非線形可積分系の代表例であるKP階層や戸田格子階層の準周期解は、タイヒミュラー保型形式の重要な例を与えるが、上記の漸近公式を用いてこの準周期解の変動を研究し、準周期解とソリトン解の混合物として表されるKP・戸田格子階層の解の一般的な表示を得た。特にトロピカル曲線から定まるテータ関数のトロピカル化を準周期解の極限として表すことにより、ソリトン解の非常に広いクラスを構成した。
    2.与えられた種数を持つ任意のマンフォード曲線とショットキー一意化されたリーマン面を導く「普遍マンフォード曲線」を、すべての退化データに対応する高種数テイト曲線を糊付けすることによって構成し、その応用として、アーベル積分の非可換化である普遍マンフォード曲線上の巾単周期の理論を構成した。さらにその漸近的な明示公式を多重対数関数や多重ゼータ値を用いて与え、理論物理学におけるファインマン積分の計算への展望を与えた。

  • Study of the moduli space of periodic minimal surfaces by means of geometric invariants

    Grant number:20K03616  2020.4 - 2024.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Shoda Toshihiro

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    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

    A triply periodic minimal surface is a mathematical model of surfactant, and our main theme in this period is to study the moduli space of triply periodic minimal surfaces by means of three kinds of geometric invariants, namely, the Morse index, the nullity, the signature.
    <BR>
    We first focus on the genus three case, and computed the three quantities for the mPCLP/mDCLP family, which is a three parameter family and which have been studied in physics in 1990s. Next, we consider a boundary of the moduli space via the Bolza surface which is the genus two classical closed surface. We determined the three quantities around the boundary, and find a local structure of the boundary of the moduli space.

  • Arithmetic geometry of the moduli spaces of algebraic curves and abelian varieties, and its applications

    Grant number:17K05179  2017.4 - 2022.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Ichikawa Takashi

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    Grant amount:\4420000 ( Direct Cost: \3400000 、 Indirect Cost:\1020000 )

    Using an explicit formula of abelian differentials on generalized Tate curves, we give infinite product expressions of the Riemann-Roch isomorphism and the Mumford isomorphism defined for families of algebraic curves, and study the degeneration of quasi-periodic solutions of the KP hierarchy with application to its solutions obtained as mixtures of quasi-periodic and soliton solutions. Furthermore, we construct the universal Mumford curve, and show explicit formulas of its (universal) abelian differentials, period integrals and compactified Jacobians. As a nonabelian extension of this result, we give asypmtotic explicit formulas of unipotent peirods using multiple polylogarithm functions and zeta values.

  • Study of stability of periodic minimal surfaces and their limits

    Grant number:16K05134  2016.4 - 2020.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Shoda Toshihiro

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    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

    Periodic minimal surfaces in the Euclidean three-space can be considered as a mathematical model for surfactant in the soft matter. In 1990s, physicists considered many families of triply periodic minimal surfaces. On the other hand, a stability of a minimal surface has been studied via area minimizing situation. In particular, Barbosa-doCarmo's technique related to volume preserving stability might be useful tool for this situation. By this study, we find out volume preserving stability for some families which physicists considered. Moreover, we gave mathematical description of lamellar phases in the soft matter as limits of triply periodic minimal surfaces.

  • Infinite product presentation of the Mumford form and special values of geometric zeta functions

    Grant number:26400018  2014.4 - 2017.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    ICHIKAWA Takashi

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    Grant amount:\4810000 ( Direct Cost: \3700000 、 Indirect Cost:\1110000 )

    By the arithmetic Schottky-Mumford uniformization theory, we proved the arithmeticity of Chern-Simons invariants. Using this result together with the Arakelov theory in arithmetic geometry and the theory of Zograf, Mcintyre-Takhatajan on the classical Liouville field theory, we gave an infinite product presentation of the Deligne-Riemann-Roch isomorphism which expresses the Chern-Simons line bundle. As its application, we express the special values of the Ruelle zeta functions of Schottky groups as the products of period integrals and discriminants. This result gives an analog of the Deligne conjecture on
    such geometric zeta values.

  • Arithmetical rank of Stanley-Reisner ideals and projective dimension of their powers

    Grant number:26400049  2014.4 - 2017.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Terai Naoki, YOSHIDA KENICHI, YANAGAWA KOUJI, KIMURA KYOUKO

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    Grant amount:\4810000 ( Direct Cost: \3700000 、 Indirect Cost:\1110000 )

    We studied the projective dimension of symbolic powers of squarefree monomial ideals in a polynomial ring. We proved that the projective dimension of the symbolic power of the edge ideal of a very well-covered graph increases with respect to the exponent. Since a well-covered bipartite graph is very well-covered and since the symbolic powers and ordinary powers coincide for the edge ideal of a bipartite graph, it implies that the projective dimension of the ordinary power of the edge ideal of a very well-covered graph increases. Moreover, we showed that the projective dimension of the symbolic power of the edge ideal of a graph with a vertex of degree one increases with respect to the exponent.

  • New methods on geometric analysis of variational problems for surfaces

    Grant number:25287012  2013.4 - 2017.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    KOISO Miyuki, CHENG Qing-Ming, MIYAMOTO Umpei, EJIRI Norio

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    Grant amount:\10790000 ( Direct Cost: \8300000 、 Indirect Cost:\2490000 )

    Under given boundary conditions, minimal surfaces are critical points of area, and surfaces with constant mean curvature (CMC surfaces) are critical points of area among surfaces enclosing the same volume. Such a surface is said to be stable if it attains a local minimum of area for all admissible variations. In this research, we studied criteria for stability, existence and uniqueness of (stable) critical points, bifurcation of critical points, for fixed, free, and periodic boundary conditions.

  • Investigation about the educational effect of the attached school in national universities by narrative approach

    Grant number:25590226  2013.4 - 2016.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Exploratory Research

    SANAGA Takeshi, NAKAYAMA Akiko, MURAYAMA Shiho, KURIHARA Atushi, TANAKA Syouichi, KURIYAMA Hiroshi, ITABASHI Eriya, SYOUDA Toshihiro

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    Grant amount:\2990000 ( Direct Cost: \2300000 、 Indirect Cost:\690000 )

    It was investigated about the educational effect of the attached school in national university. That was chosen as the way to interview students and interpret their obtained talk (history of learning), not achievement tests.
    It's the case that students' learning is embedded in the situation of the school and the home that it became clear. Therefore learning is restricted by the situation-pressure by which it's for the school and the home. On the other hand they get a resource from situations and are expanding learning aggressively. Therefore the education which emphasized the situation of the school and the home is desired.

  • Study of the moduli theory of periodic minimal surfaces in terms of differential geometry

    Grant number:24740047  2012.4 - 2016.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    Shoda Toshihiro

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    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

    We would study periodic minimal surfaces in the Euclidean space in terms of the differential geometry. In particular, we treated Morse indices of triply periodic minimal surfaces. In this period, we could succeed in computing many Morse indices for families of minimal surfaces which have been studied in physics and chemistry. Also, we could succeed in mathematical description of Lamellar structure by limits of triply perioddic minimal surfaces. Moreover, we obtained the existence and uniqueness results for a comlete minimal surface of finite total curvature in the Euclidean space.

  • Development of Integrable Geometry

    Grant number:23340012  2011.4 - 2015.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Miyaoka Reiko, KOTANI Motoko, NISHINOU Takeo, UEHARA Taketo, MATSUURA Nozomu, IWASAKI Katsunori, IRITANI Hiroshi, KAJIWARA Kenji, NAGATOMO Yasuyuki, NOMURA Takaaki, YAMADA Kotaro, ISHIKAWA Goo, UMEHARA Masaaki, GUEST Martin, SHODA Toshihiro, FUTAKI Akito, FUJIOKA Atsushi, RASSMAN Wayne, TAMARU Hiroshi

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    Grant amount:\13780000 ( Direct Cost: \10600000 、 Indirect Cost:\3180000 )

    Isoparametric hypersurfaces with 6 principal curvatures with multiplicity 2 are shown to be homogeneous, which solves one of Yau's problems. As for 4 principal curvature case, we gave a description by using the moment map of spin actions. Transnormal systems are investigated in details.
    We show the non-existence of L2 harmonic 1-form on a complete non-compact stable minimal Lagrangian submanifolds in a Kaheler manifold with positive Ricci curvature. Then the number of non-parabolic ends is less than two, and in the surface case, the genus should vanish. The Floer theory on the intersection of a Lagrangian submanifold with its Hamiltonian deformation is investigated. The Gauss images of isoparametric hypersurfaces in the sphere are Lagrangian submanifolds of complex hyperquadric, and in this case, we show that if the multiplicities of the principal curvatures are bigger than 1, then they are Hamiltonian non-displaceable,

  • Stability and bifurcation for periodic minimal surfaces and surfaces with constant mean curvature, and applications to other fields

    Grant number:22654009  2010 - 2012

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Exploratory Research

    KOISO Miyuki, YAMADA Kotaro, SHODA Toshihiro, FUJIMORI Shoichi, KAWAKUBO Satoshi

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    Grant amount:\3110000 ( Direct Cost: \2600000 、 Indirect Cost:\510000 )

    We studied surfaces with constant mean curvature and surfaces with constant anisotropic mean curvature with free or fixed boundary. We obtained results about existence, uniqueness, geometric properties of solutions or stable solutions. Also, we obtained sufficient conditions for the existence of bifurcationand criterion of the stability for each surface in the bifurcation branch. Moreover,by removing the convexity assumption for the anisotropic surface energy, we studied uniformly a large class of surfaces including constant mean curvature surfaces in the Lorentz-Minkowski space and obtained a new uniqueness theorem and examples.

  • Moduli space of minimal surfaces with Galois Theory

    Grant number:20740042  2008 - 2011

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    SHODA Toshihiro

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    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

    We usually call the set of all minimal surfaces" Moduli space of minimal surfaces". To consider the Moduli space of minimal surfaces, it is important to study Period map on the Moduli space of minimal surfaces. We have calculated periods of many examples of minimal surfaces. From the experiences, we conjecture that there may be symmetry by solvable group in Galois Theory. Thus, we will establish the Moduli theory of minimal surfaces in terms of the Galois Theory.

  • The development and fusion on the geometry of submanifolds and theory for eigenvalues of the differential operators in Riemannian manifolds

    Grant number:20540082  2008 - 2010

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    CHENG Qing-Ming, KAWAI Shigeo, MAEDA Sadahiro, SHODA Toshihiro

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    Grant amount:\4420000 ( Direct Cost: \3400000 、 Indirect Cost:\1020000 )

    In this project, by making use of fusion on the research methods in the geometry of submanifolds and the research methods for eigenvalues of the differential operators on bounded domains in Riemannian manifolds, we can construct trial functions with good properties such that we obtain a sharp universal inequalityfor eigenvalues of the Dirichlet eigenvalue problem of the Laplacian on bounded domainsin Riemannian manifolds and a universal inequality for eigenvalues of the clamped plate problem. Furthermore, by combining the universal inequality for eigenvalues with therecursion formula of Cheng and Yang, we give the upper bounds for the k-th eigenvalueof the Dirichlet eigenvalue problem of the Laplacian on bounded domains in Riemannian manifolds. It is optimal in the sense of the order of k. By using a new and original method replacing the method of the Fourier transform, we obtain a Li-Yau type lower bound for eigenvalues of the Dirichlet eigenvalue problem of the Laplacian on bounded domains in Riemannian manifolds. About the study on lower bounds for eigenvalues of the clamped plate problem on bounded domains in a Euclidean space, we improve the inequality of Levine and Protter by using the Fourier transform and the symmetry rearrangement of a domain. On the other hand, we study structures of curvatures and topological structures of submanifolds according to several different view points. An optimal upper bound for the first eigenvalue of Jacobi operator of compact hypersurfaces with constant scalar curvature in the unit sphere is given. Many embedded compact hypersurfaces with constantk-th mean curvature in the unit sphere are constructed.

  • Fusion of geometry and the theory of integrable systems

    Grant number:19204006  2007 - 2010

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    MIYAOKA Reiko, OHNITA Yoshihiro, MOTOKO Kotani, SASAKI Takeshi, IWASAKI Katsunori, OYSU Yukio, KAJIWARA Kenji, NAGATOMO Yasuyuki, NAKAYAAHIKI Atsushi, YAMADA Kotaro, FUTAKI Akito, MARTIN Guest, WAYNE Rossman, SHODA Toshihiro, IRITANI Hiroshi, ISHIKAWA Goo, UMEHARA Masaaki, KAWAKUBO Satoshi, TAMARU Hiroshi, FUJIOKA Atsushi, MATSUURA Nozomu, NISHINOU Takeo

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    Grant amount:\27560000 ( Direct Cost: \21200000 、 Indirect Cost:\6360000 )

    We classified almost all isoparametric hypersurface, and characterize them in terms of the moment map, which proves the evidence of a relation with integrable systems. A basic theory of surfaces with singularities, and a new method using the Legendre map have been established. Via the Riemann-Hilbert correspondence, the dynamical system of Painleve equations is investigated, and the view point of the chaos has been developed. The modularity of higher genus Gromov-Witten and the mirror symmetry are discussed. A surface with potential appeared in quantum cohomology is constructed, which contributes to the tt* geometry.

  • Generalizations of Weierstrass-type representation formula and their applications to theory of surface with singularities

    Grant number:18340019  2006 - 2008

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    YAMADA Kotaro, MIYAOKA Reiko, SAEKI Osamu, OTSU Yukio, NAGATOMO Yasuyuki, TAKAYAMA Haruko, UMEHARA Masaaki, KUROSE Takashi, KOKUBU Masatoshi, FUJIMORI Shoichi, SHODA Toshihiro, TAKAHASHI Masaro

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    Grant amount:\8740000 ( Direct Cost: \7300000 、 Indirect Cost:\1440000 )

    Properties of certain classes of surfaces with singularities are investigated with Weirstrass-type representation formula. For example, global behavior of flat fronts, and behavior of singularities of maximal surfaces in Lorentz-Minkowski 3-space and mean curvature one surfaces in de Sitter 3-space are investigated.
    On the other hand, as a general theory of differential geometry of singularities, a notion of singular curvature of the singular points of wave fronts is defined, and Gauss-Bonnet type formulas are obtained.

  • ユークリッド空間または平坦トーラス内の極小曲面における正則性及びモジュライの研究

    Grant number:05J05835  2005 - 2007

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    庄田 敏宏

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    Grant amount:\1100000 ( Direct Cost: \1100000 )

    本年度の研究課題はSpecial Lagrangian多様体を幾何学的測度論の観点から研究する事であった.そのために体積最小に関する古典的な部分多様体である極小曲面の研究方法をSLの研究へと適応する事を試みた.その前段階として平坦トーラス内の極小曲面に関する研究を行った.
    まず4次元平坦トーラス内の極小曲面において,筆者による先行研究の具体例よりも種数の高い具体例を構成した.今回構成した具体例は長野-Smythによる結果の逆が一般には成り立たない事を示すのみならず,極小曲面全体のモジュライの研究に関係するものである.また,その後イギリスのWarwick大学のスタッフであるM.Micallef氏のもとに滞在し,この具体例の指数に関する研究を行った結果,それは6以上である事が判った.次に6次元平坦トーラス内の安定極小曲面でトーラスのどのような複素構造に対しても複素正則にならないような安定極小曲面の存在に関する研究を行った.この問題はC.Arezzp, Micallef, R.Schoenをはじめとして多くの研究者の興味をひくものであり,未だ解決されていない問題である.その第一歩としてまず具体例の構成を考えた.構成の手段として,5次元平坦トーラス内の極小曲面からそれを1助変数にて変形して6次元平坦トーラス内の複素正則な極小曲面を構成した.現在,その複素正則な極小曲面に近い極小曲面における安定性を考察中である.さらに,神戸大の藤森祥一氏との共同研究にて,筆者による3次元平坦トーラス内の極小曲面の具体例のグラフィックスおよびその構造が明らかになった.これは6本の閉折れ線によるPlateau問題の解となる極小曲面を鏡像の原理で増やしたものである.残念ながら本研究が目指す結び目に関するPlateau問題による構成ではないものの十分にその価値を評価しうるものである事が判った.

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