Updated on 2025/03/27

写真a

 
Kinjo Erina
 
Organization
Graduate School of Science and Engineering (Engineering) Major of Science and Engineering Mechanical Engineering Assistant Professor
Title
Assistant Professor
Contact information
メールアドレス
External link

Degree

  • 博士(理学) ( 2012.9   東京工業大学 )

Research Interests

  • 複素解析,リーマン面,タイヒミュラー空間,擬等角写像,双曲幾何学

Research Areas

  • Natural Science / Basic analysis  / 複素解析

Education

  • Tokyo Institute of Technology

    2008.4 - 2012.9

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  • Tokyo Institute of Technology

    2006.4 - 2008.3

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Professional Memberships

Papers

  • On countability of Teichmüller modular groups for analytically infinite Riemann surfaces defined by generalized Cantor sets

    Erina Kinjo

    Proceedings of the Japan Academy, Series A, Mathematical Sciences   100 ( 10 )   2024.12

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    Publishing type:Research paper (scientific journal)   Publisher:Project Euclid  

    DOI: 10.3792/pjaa.100.013

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  • On the length spectrums of Riemann surfaces given by generalized Cantor sets

    Kinjo Erina

    Kodai Mathematical Journal   47 ( 1 )   34 - 51   2024.3

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    Language:English   Publisher:Department of Mathematics, Tokyo Institute of Technology  

    For a generalized Cantor set <i>E</i>(<i>ω</i>) with respect to a sequence <img align="middle" src="./Graphics/abst-1.jpg"/>, we consider Riemann surface <img align="middle" src="./Graphics/abst-2.jpg"/> and metrics on Teichmüller space <i>T</i>(<i>X</i><sub><i>E</i>(<i>ω</i>)</sub>) of <i>X</i><sub><i>E</i>(<i>ω</i>)</sub>. If <i>E</i>(<i>ω</i>) = <img align="middle" src="./Graphics/abst-3.jpg"/> (the middle one-third Cantor set), we find that on <img align="middle" src="./Graphics/abst-4.jpg"/>, Teichmüller metric <i>d</i><sub><i>T</i></sub> defines the same topology as that of the length spectrum metric <i>d</i><sub><i>L</i></sub>. Also, we can easily check that <i>d</i><sub><i>T</i></sub> does not define the same topology as that of <i>d</i><sub><i>L</i></sub> on <i>T</i>(<i>X</i><sub><i>E</i>(<i>ω</i>)</sub>) if sup <i>q</i><sub><i>n</i></sub> = 1. On the other hand, it is not easy to judge whether the metrics define the same topology or not if inf <i>q</i><sub><i>n</i></sub> = 0. In this paper, we show that the two metrics define different topologies on <i>T</i>(<i>X</i><sub><i>E</i>(<i>ω</i>)</sub>) for some <img align="middle" src="./Graphics/abst-5.jpg"/> such that inf <i>q</i><sub><i>n</i></sub> = 0.

    DOI: 10.2996/kmj47103

    DOI: 10.48550/arxiv.2211.04897

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  • On the length spectrum Teichmüller spaces of Riemann surfaces of infinite type

    Erina Kinjo

    Conformal Geometry and Dynamics of the American Mathematical Society   22 ( 1 )   1 - 14   2018.2

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    Publisher:American Mathematical Society (AMS)  

    On the Teichmüller space <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper T left-parenthesis upper R 0 right-parenthesis">
    <mml:semantics>
    <mml:mrow>
    <mml:mi>T</mml:mi>
    <mml:mo stretchy="false">(</mml:mo>
    <mml:msub>
    <mml:mi>R</mml:mi>
    <mml:mn>0</mml:mn>
    </mml:msub>
    <mml:mo stretchy="false">)</mml:mo>
    </mml:mrow>
    <mml:annotation encoding="application/x-tex">T(R_0)</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula> of a hyperbolic Riemann surface <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R 0">
    <mml:semantics>
    <mml:msub>
    <mml:mi>R</mml:mi>
    <mml:mn>0</mml:mn>
    </mml:msub>
    <mml:annotation encoding="application/x-tex">R_0</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula>, we consider the length spectrum metric <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="d Subscript upper L">
    <mml:semantics>
    <mml:msub>
    <mml:mi>d</mml:mi>
    <mml:mi>L</mml:mi>
    </mml:msub>
    <mml:annotation encoding="application/x-tex">d_L</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula>, which measures the difference of hyperbolic structures of Riemann surfaces. It is known that if <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R 0">
    <mml:semantics>
    <mml:msub>
    <mml:mi>R</mml:mi>
    <mml:mn>0</mml:mn>
    </mml:msub>
    <mml:annotation encoding="application/x-tex">R_0</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula> is of finite type, then <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="d Subscript upper L">
    <mml:semantics>
    <mml:msub>
    <mml:mi>d</mml:mi>
    <mml:mi>L</mml:mi>
    </mml:msub>
    <mml:annotation encoding="application/x-tex">d_L</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula> defines the same topology as that of Teichmüller metric <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="d Subscript upper T">
    <mml:semantics>
    <mml:msub>
    <mml:mi>d</mml:mi>
    <mml:mi>T</mml:mi>
    </mml:msub>
    <mml:annotation encoding="application/x-tex">d_T</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula> on <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper T left-parenthesis upper R 0 right-parenthesis">
    <mml:semantics>
    <mml:mrow>
    <mml:mi>T</mml:mi>
    <mml:mo stretchy="false">(</mml:mo>
    <mml:msub>
    <mml:mi>R</mml:mi>
    <mml:mn>0</mml:mn>
    </mml:msub>
    <mml:mo stretchy="false">)</mml:mo>
    </mml:mrow>
    <mml:annotation encoding="application/x-tex">T(R_0)</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula>. In 2003, H. Shiga extended the discussion to the Teichmüller spaces of Riemann surfaces of infinite type and proved that the two metrics define the same topology on <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper T left-parenthesis upper R 0 right-parenthesis">
    <mml:semantics>
    <mml:mrow>
    <mml:mi>T</mml:mi>
    <mml:mo stretchy="false">(</mml:mo>
    <mml:msub>
    <mml:mi>R</mml:mi>
    <mml:mn>0</mml:mn>
    </mml:msub>
    <mml:mo stretchy="false">)</mml:mo>
    </mml:mrow>
    <mml:annotation encoding="application/x-tex">T(R_0)</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula> if <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R 0">
    <mml:semantics>
    <mml:msub>
    <mml:mi>R</mml:mi>
    <mml:mn>0</mml:mn>
    </mml:msub>
    <mml:annotation encoding="application/x-tex">R_0</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula> satisfies some geometric condition. After that, Alessandrini-Liu-Papadopoulos-Su proved that for the Riemann surface satisfying Shiga’s condition, the identity map between the two metric spaces is locally bi-Lipschitz.



    In this paper, we extend their results; that is, we show that if <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R 0">
    <mml:semantics>
    <mml:msub>
    <mml:mi>R</mml:mi>
    <mml:mn>0</mml:mn>
    </mml:msub>
    <mml:annotation encoding="application/x-tex">R_0</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula> has bounded geometry, then the identity map <inline-formula content-type="math/mathml">
    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis upper T left-parenthesis upper R 0 right-parenthesis comma d Subscript upper L Baseline right-parenthesis right-arrow left-parenthesis upper T left-parenthesis upper R 0 right-parenthesis comma d Subscript upper T Baseline right-parenthesis">
    <mml:semantics>
    <mml:mrow>
    <mml:mo stretchy="false">(</mml:mo>
    <mml:mi>T</mml:mi>
    <mml:mo stretchy="false">(</mml:mo>
    <mml:msub>
    <mml:mi>R</mml:mi>
    <mml:mn>0</mml:mn>
    </mml:msub>
    <mml:mo stretchy="false">)</mml:mo>
    <mml:mo>,</mml:mo>
    <mml:msub>
    <mml:mi>d</mml:mi>
    <mml:mi>L</mml:mi>
    </mml:msub>
    <mml:mo stretchy="false">)</mml:mo>
    <mml:mo stretchy="false">→<!-- → --></mml:mo>
    <mml:mo stretchy="false">(</mml:mo>
    <mml:mi>T</mml:mi>
    <mml:mo stretchy="false">(</mml:mo>
    <mml:msub>
    <mml:mi>R</mml:mi>
    <mml:mn>0</mml:mn>
    </mml:msub>
    <mml:mo stretchy="false">)</mml:mo>
    <mml:mo>,</mml:mo>
    <mml:msub>
    <mml:mi>d</mml:mi>
    <mml:mi>T</mml:mi>
    </mml:msub>
    <mml:mo stretchy="false">)</mml:mo>
    </mml:mrow>
    <mml:annotation encoding="application/x-tex">(T(R_0),d_L) \to (T(R_0),d_T)</mml:annotation>
    </mml:semantics>
    </mml:math>
    </inline-formula> is locally bi-Lipschitz.

    DOI: 10.1090/ecgd/316

    DOI: 10.2996/kmj47103_references_DOI_X23C6T8ShAU2F19MhqGjlpPISpd

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  • On the length spectrum metric in infinite dimensional Teichmüller spaces

    Erina Kinjo

    Annales Academiae Scientiarum Fennicae Mathematica   39   349 - 360   2014.2

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    Publisher:Finnish Mathematical Society  

    We consider the length spectrum metric dL in infinite dimensional Teichmuller space T(R0). It is known that dL defines the same topology as that of the Teichmuller metric dT on T(R0) if R0 is a topologically finite Riemann surface. In 2003, Shiga proved that dL and dT define the same topology on T(R0) if R0 is a topologically infinite Riemann surface which can be decomposed into pairs of pants such that the lengths of all their boundary components except punctures are uniformly bounded by some positive constants from above and below. In this paper, we extend Shiga's result to Teichmuller spaces of Riemann surfaces satisfying a certain geometric condition.

    DOI: 10.5186/aasfm.2014.3925

    DOI: 10.2996/kmj47103_references_DOI_OKdZk8UcNpC8HendkgJSkxDCYpK

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  • On Teichmüller metric and the length spectrums of topologically infinite Riemann surfaces

    Erina Kinjo

    Kodai Mathematical Journal   34 ( 2 )   2011.6

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    Publishing type:Research paper (scientific journal)   Publisher:Tokyo Institute of Technology, Department of Mathematics  

    DOI: 10.2996/kmj/1309829545

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