#norelated
 
 //*** [[FrontPage]] [#zc9a1572]
 
 
 //#contents
 
 
 [[講演・口頭発表等:https://researchmap.jp/read0051534/presentations?lang=ja]]
 
 //[[研究発表:https://info.ibaraki.ac.jp/Profiles/17/0001645/detail.html?lang=ja&achievement=meeting_achievement]](茨城大学研究者情報総覧)
 
 ////////////////////////////////////////////////////////
 ** Talks in international conferences or invited talks [#ee804610]
 
 
 
 - 2024-06(scheduled)
 '''Positive solutions for logistic type elliptic equation with a non Lipschitz boundary condition arising in coastal fishery harvesting''', [[Equadiff 2024:https://www.kau.se/equadiff-2024/about-conference]]
 '''Positive solutions for logistic type elliptic equation with a non Lipschitz boundary condition arising in coastal fishery harvesting''', [[Equadiff 2024:https://www.kau.se/equadiff]]
 ([[Karlstad University:https://www.kau.se/]], Sweden, June 10-14, 2024). 
 
 - 2023-06-01
 '''An exact multiplicity result for some sublinear Robin problem with an indefinite weight (with UK and HRQ) (invited)''', in the special session (SS3) of 
 [[The 13th AIMS Conference on Dynamical Systems, Differential Equations and Applications:https://www.aimsconference.org/conferences/2023/index.html]] ([[University of North Carolina Wilmington:https://uncw.edu/]], [[Wilmington:https://bit.ly/41FPDEj]], USA, May 31-June 4, 2023). 
 [[slides:https://drive.google.com/file/d/1KtyBIu2DDjWxAfFa0Wa-id2DQXZLE_Wt/view?usp=sharing]] 
 //&ref(umezu_SS3_11.pdf);
 
 
 //- 2020-06 (&color(red){''rescheduled, postponed to June, 2021''};) 
 //'''A global exact multiplicity result for positive solutions of the indefinite sublinear Robin problem (with UK and HRQ) (invited)''', in the special session (SS27) of [[The 13th AIMS Conference on Dynamical Systems, Differential Equations and //Applications:http://www.aimsciences.org/conferences/2020/index.html]] (Atlanta, USA, June 5-9, 2020). 
 
 
 - 2019-07-11, 
 '''Existence of a loop of positive solutions for concave-convex problems with indefinite weights (with UK and HRQ)''', 
 [[Equadiff 2019:https://www.universiteitleiden.nl/equadiff2019]] 
 ([[Leiden University:https://www.universiteitleiden.nl/en]], Leiden, The Netherlands, July 8-12 2019). 
 [[the poster:http://pub.math.leidenuniv.nl/~hupkeshj/poster.pdf]] 
 [[slides:https://drive.google.com/file/d/1bXR_VSh4hSvNr98JG5nL5Ew1dCcbpHjZ/view?usp=sharing]] 
 //&ref(equadiff2019.pdf);
 
 
 - 2018-07-06, '''Positivity of bifurcating nontrivial nonnegative solutions of indefinite concave problems (with Uriel Kaufmann and HRQ) (invited)''', IN the Special Session `Nonlinear Elliptic and Parabolic Problems (SS17)', organized by Prof. Sze-Bi Hsu and Prof. Julian Lopez-Gomez, [[The 12th AIMS Conference on Dynamical Systems, Differential Equations and Applications:http://www.aimsciences.org/conferences/2018/index.html]] ([[National Taiwan University:https://www.ntu.edu.tw/english/]], Taipei, Taiwan, July 5-9, 2018). [[slides:https://drive.google.com/file/d/1MrXkEOL2JqLUMvFmdZqWRpsJYSOIcKKl/view?usp=sharing]] 
 //&ref(umezu_ss17.pdf);
 
 
 ////////////////////////////////////
 - 2016-10-08, '''On the existence of a loop component of nontrivial non-negative solutions for some concave-convex problem (with HRQ) (invited)''', Workshop on reaction diffusion equations and numerical analysis (Kyoto Sangyo University, Kyoto, October 8, 2016). [[slides:https://drive.google.com/file/d/1fbVBEVErIFIHREAnWcdfVHuFs4_ki8BP/view?usp=sharing]] 
 
 
 
 //////////////////////////////////////
 - 2016-07-04, '''A loop type component of positive solutions of an indefinite concave-convex problem with the Neumann boundary condition(with Humberto Ramos Quoirin)(invited)''', IN the Special Session SS36 `New Trends in Nonlinear Partial Differential Equations and Applications' organized by Prof. J.L\'opez-G\'omez, [[The 11th AIMS Conference on Dynamical Systems, Differential Equations and Applications:http://www.aimsciences.org/conferences/2016/index.html]] (Orlando, Florida, USA, July 1-5, 2016). [[slides:https://drive.google.com/file/d/1hZeNkjPvGFGyjmwxx3jSTd0AWPS3Uukb/view?usp=sharing]] 
 // slides &ref(orlando2016.pdf);
 
 
 
 
 
 - 2015-11-13, 
 // (in English, 50min) 
 '''An indefinite superlinear elliptic equation with a nonlinear boundary condition of sublinear type (with Humberto Ramos Quoirin) (invited)''', RIMS Workshop `Shapes and other properties of solutions of PDEs' (RIMS, Kyoto University, November 11-13, 2015). [[slides:https://drive.google.com/file/d/1j2HqFdfgsKgqbppbkppLrV1kOG4fu7tO/view?usp=sharing]]
 
 
 - 2015-09-01, 
 // (in English, 50 min)
 '''Bifurcation analysis for a logistic elliptic equation having nonlinear boundary conditions with sign-definite weights (invited)''', IN the Math Department Seminar of [[Universidad de Santiago de Chile:https://www.usach.cl/]]. [[slides:https://drive.google.com/file/d/1SEwcWRsn9VjlLmnvHU3X5RXL6J5nviA8/view?usp=sharing]]
 
 
 
 - 2014-07-08, 
 '''The effect of a nonlinear boundary condition with an indefinite weight on the positive solution set of the logistic elliptic equation (with Humberto Ramos Quoirin) (invited)''', IN the special session '''Nonlinear Elliptic and Parabolic Problems (SS18)''' organized by Prof. L\'opez-G\'omez in [[The 10th AIMS Conference on Dynamical Systems, Differential Equations and Applications:http://aimsciences.org/conferences/2014/index.html]] (Madrid, Spain, July 7-11, 2014). [[slides:https://drive.google.com/file/d/1t60wWs70li2sGjOfCZWWQXBSyHAU2WJb/view?usp=sharing]]
 // for presentation &ref(Madrid2014.pdf);
 
 
 
 - 2012-07-04, 
 '''On the effect of spatial heterogeneity in logistic type elliptic equations with nonlinear boundary conditions (invited)''', The Special Session SS55 '''Nonlinear Elliptic and Parabolic Problems''' organized by Prof. L\'opez-G\'omez in [[The 9th AIMS Conference on Dynamical Systems, Differential Equations and Applications:http://www.aimsciences.org/conferences/2012/index.html]] (Orlando, Florida, USA, July 1-5, 2012). [[slides:https://drive.google.com/file/d/1p1bp2NRl4zXNp8EjlI-v_cY_pRGppho5/view?usp=sharing]] 
 // for presentation &ref(orlando2012.pdf);
 
 
 
 
 
 - 2010-05-27,  
 '''Global bifurcation analysis of indefinite nonlinear boundary value problems with nonlinear boundary conditions (invited)''', 
 IN The 8th AIMS Conference on Dynamical Systems, Differential Equations and Applications ([[Dresden University of Technology:https://tu-dresden.de/?set_language=en]], Dresden, Germany, 
 May 25-28, 2010). [[abstract:https://drive.google.com/file/d/1Hes3FCP9vbjmAJgt3DuMGSIjmV4mV8Zz/view?usp=sharing]]
 // &ref(10dresden-abst.pdf); 
 [[slides:https://drive.google.com/file/d/1UI28Rp2jIxgF6sf_P_mJVC9QIz-SC_XV/view?usp=sharing]]
 // slides for presentation &ref(dresden2010.pdf);
 
 
 
 
 - 2008-08-06, 
 '''Blowing-up properties of the positive principal eigenvalue for indefinite Robin-type boundary conditions''',  IN The Second China-Japan Colloquium of Mathematical Biology (Okayama University, August 4-7, 2008). 
 [[slides:https://drive.google.com/file/d/1g20IGK4J_ygoFSS9iAVJL9fJsWi9asT2/view?usp=sharing]]
 //  for presentation &ref(08okayama.pdf);
 
 
 
 
 - 2007-06-27, 
 '''Multiplicity of positive solutions to nonlinear elliptic boundary value problems arising in population dynamics''', IN Workshop "[[Direct, Inverse And Control Problems For PDE's:http://www.dm.unibo.it/convegni/dicop07/]]" (Rome, Italy, June 25-28, 2007).
 
 
 
 
 - 2007-06-01, 
 '''Principal eigenvalues of Neumann and Robin type eigenvalue problems with indefinite weights (invited)''', IN [[The 4th International Conference on Mathematical Biology:http://icmb.mnkjxy.com/english.htm]] (Wuyishan, Fujian, P.R. China, May 29 - June 1, 2007).
 
 
 
 
 - 2006-04-25, 
 '''Blowing-up behavior of principal eigenvalues for Neumann boundary conditions''', IN The first China-Japan Colloquium of Mathematical Biology (CJCMB) ([[Southwest University:http://gjxy.swu.edu.cn/ywb/Home.htm]], Chongqing, China, 24-28 April 2006). 
 [[slides:https://drive.google.com/file/d/19I5L2NtnCQBtul03Y_JE-ydN6Ot43jq5/view?usp=sharing]]
 // for presentation &ref(mbio.pdf);
 
 
 
 
 - ISAAC05, the 5th Congress, '''Elliptic eigenvalue problems with indefinite Robin boundary conditions (invited)''', [[University of Catania:https://www.unict.it/en]], Italy, 25-30 July 2005.
 
 
 
 
 - Nonlinear Elliptic and Parabolic Problems: A Special Tribute to the Work of Herbert Amann, '''Existence and nonexistence of positive solutions for a semilinear elliptic problem arising in population dynamics''', [[University of Zurich:https://www.uzh.ch/en.html]], Zurich, 28-30 June 2004.
 
 
 
 
 - ISAAC03, the 4th Congress, '''On diffusive logistic equations having nonlinear boundary conditions (invited)''', [[York University:https://www.yorku.ca/]], Toronto, 11-16 August 2003.
 
 
 
 
 - International Conference on Nonlinear Partial Differential Equations Theory and Approximation, '''Bifurcation problem for a semilinear elliptic equation arising in population dynamics, having nonlinear boundary conditions''', [[City University of Hong Kong:https://www.cityu.edu.hk/]], Hong Kong, 29 August - 2 September 2002.
 
 
 
 
 - The 4th European Conference on Elliptic and Parabolic Problems, '''Bifurcation in population dynamics''', Gaeta, Italy, 24-28 September 2001.
 
 
 - ISAAC01, the 3rd Congress, '''Bifurcation analysis in diffusive logistic equations with nonlinear boundary conditions (invited)''', [[Freie University, Berlin:https://www.fu-berlin.de/en/index.html]], 20-25 August 2001.
 
 
 - International Conference on Nonlinear Partial Differential Equations 99, '''Bifurcation and stability for diffusive logistic equations with nonlinear boundary conditions''', [[Lviv State University:https://lnu.edu.ua/en/]], Ukraine, 24-28 August 1999.
 
 
 - ICIAM 99, the 4th Congress, '''Elliptic boundary value problems with nonlinear boundary conditions (invited)''', [[University of Edinburgh:https://www.ed.ac.uk/]], Scotland, 5-9 July 1999.
 
 
 - ISAAC97, the 1st Congress, '''Semilinear elliptic boundary value problems in chemical reactor theory''', [[University of Delaware:https://www.udel.edu/]], USA, 3-6 June 1997. 
 
 /////////////////////////////////////////////////////////////////////
 ** General talks in Mathematical Society Meetings of Japan [#r5b0691a]
 // 日本数学会 [#oc855d5f]
 
 
 - 2020-03-16 
 Global exact multiplicity of positive solutions for an indenite sublinear Robin problem, 2020年年会函数方程式論分科会(日大理工).
 
 
 - 2019-03-17 
 Exact multiplicity of positive solutions for an indefinite concave Robin bvp, 2019年年会函数方程式論分科会(東工大).[[スライド:https://drive.google.com/file/d/1imwqfkK2H7UEFJeCFd_yZUGu0vYk1KM7/view?usp=sharing]]
 // &ref(19tit.pdf);
 
 
 - 2018-03-18
 Loop components of nontrivial nonnegative solutions for indefinite concave-convex problems, 2018年年会函数方程式論分科会(東大数理).[[スライド:https://drive.google.com/file/d/1IJuVGpooS39LsJ_PcOfSMIWTSLlDpLlX/view?usp=sharing]]
 // &ref(18tokyo.pdf);
 
 - 2017-03-24 
 Positivity for nontrivial nonnegative solutions of an indefinite sublinear 
 problem, 2017年年会函数方程式論分科会(首都大学東京).[[スライド:https://drive.google.com/file/d/1vJhx6V7oYNg6zTGGFhYpxo-zXVKBAVim/view?usp=sharing]]
 // &ref(17shutodai.pdf);
 
 //////////////////////
 - 2015-03-21
 convex-concave 混合型境界値問題の解構造における不定符号係数の役割について,
 2015年年会函数方程式論分科会(明治大学総合数理学部).[[スライド:https://drive.google.com/file/d/1p1bp2NRl4zXNp8EjlI-v_cY_pRGppho5/view?usp=sharing]]
 // &ref(15meiji.pdf);
 
 ////////////////////
 - 2014-03-17
 On '''S'''-shaped and '''CS'''-shaped bifurcation diagrams in population dynamics, 
 2014年年会函数方程式論分科会
 (学習院大学理学部).[[スライド:https://drive.google.com/file/d/1-D2qPXhb9eZZ1372aEjkxm4pk3KbCYWh/view?usp=sharing]]
 //  for presentation &ref(14gakushuin02.pdf);
 
 /////////////////////////////////////////
 - 2010-03-25
 Global bifurcation for indefinite weighted elliptic 
 problems with nonlinear boundary conditions, 
 2010年年会函数方程式論分科会
 (慶應義塾大学理工学部).[[スライド:https://drive.google.com/file/d/1aEv_y1DVXhZhY79bbtxybl85YTTs1FKo/view?usp=sharing]]
 // slides for presentation &ref(10keio.pdf);
 
 //////////////////
 - 2008-09-25
 A super and subsolution method for sublinear 
 problems with low regularity coefficients, 
 日本数学会'08総合分科会函数方程式論分科会
 (東京工業大学理工学研究科).[[スライド:https://drive.google.com/file/d/1HAYJlLocByPmM9AShz9I3U8SJKk0lp-L/view?usp=sharing]]
 // slides for presentation &ref(08titech.pdf);
 
 - 2007-03-28, 
 主固有値の爆発と人口動態,
 日本数学会'07年会函数方程式論分科会(埼玉大学理学部).[[スライド:https://drive.google.com/file/d/1-6letvqqBaqG_1n2kwswT05Xr76ofq4g/view?usp=sharing]]
 // slide for presentation &ref(07saitama.pdf);
 
 
 - Mar. 2006, 
 符号不定な重み係数をもつロバン型境界条件に対する
 主固有値の特徴付け, 
 日本数学会'06年会函数方程式論分科会(中央大学理工学部).
 
 
 - Mar. 2005, 
 An estimate for turning points in sublinear elliptic boundary value problems, 
 日本数学会'05年会函数方程式論分科会(日本大学理工学部).
 
 
 - Sep. 2003, 
 Existence and limiting behavior of positive solutions for 
 diffusive logistic equations with nonlinear flux on 
 the boundary, 
 日本数学会'03総合分科会函数方程式論分科会(千葉大学理学部).
 
 
 - Mar. 2002, 
 Global subcontinua arising in population dynamics, 
 日本数学会'02年会函数方程式論分科会(明治大学理工学部).
 
 
 
 - Mar. 2001, 
 Bifurcation in Population Genetics, 
 日本数学会'01年会函数方程式論分科会(慶應義塾大学理工学部).
 
 
 
 
 - Mar. 2000, 
 Bifurcation from infinity and uniqueness of 
 positive solutions to semilinear elliptic equations with nonlinear 
 boundary conditions, 
 日本数学会'00年会函数方程式論分科会(早稲田大学理工学部).
 
 
 
 - 30 Mar. 2000, 
 非線形境界条件における人口動態モデルの正値解の挙動,
 日本数学会'00年会函数方程式論分科会(早稲田大学理工学部).
 
 
 
 - Mar. 1999, 
 化学反応論における漸近安定性, 
 日本数学会'99春年会函数方程式論分科会(学習院大学理学部).
 
 
 
 
 
 - Oct. 1998, 
 Positive solutions of semilinear elliptic boundary 
 value problems, 
 日本数学会'98秋季函数方程式論分科会(大阪大学理学研究科).
 
 
 
 - Mar. 1998, 
 化学反応論における安定性, 
 日本数学会'98年会函数方程式論分科会(名城大学理学部).
 
 
 - Apr. 1997, 
 化学反応論における半線型楕円型境界値問題, 
 日本数学会'97年会函数方程式論分科会(信州大学理学部).
 
 
 
 - Apr. 1996, 
 半線形楕円型境界値問題の正値解の一意存在定理, 
 日本数学会'96年会函数方程式論分科会(新潟大学理学部).
 
 
 
 - Sep. 1995, 
 非線形楕円型境界値問題の正値解の一意存在定理, 
 日本数学会'95秋季函数方程式論分科会(東北大学理学部).
 
 
 - Mar. 1995, 
 非線形楕円型境界値問題の解の分岐定理, 
 日本数学会'95年会函数方程式論分科会(立命館大学理工学部).
 
 
 - Sep. 1993, 
 2階楕円型作用素に対する混合型境界値問題の $L^p$ アプローチ, 
 日本数学会'93秋季函数方程式論分科会(大阪府立大学総合科学部).
 
 
 // ---------------------------------------------
 
 ** Others [#oeb426d6]
 // ** セミナー、研究集会等 [#v5ed99f4]
 
 - 2023-07-07, 
 Positive solutions for some sublinear Robin problem with an indefinite weight, [[茨城大学金曜セミナー:http://enakai.sci.ibaraki.ac.jp/frisemi/]].[[スライド:https://drive.google.com/file/d/1vcSLm2_B7uGzAcDjNlmWi9IrsDQHH7VZ/view?usp=sharing]]
 
 
 ///////////////////////////
 - 2022-06-09, 
 Logistic elliptic equations with the nonlinear boundary condition arising in coast fishery harvesting, [[東北大学応用数理解析セミナー:http://www.math.tohoku.ac.jp/~tams/index.html]].
 
 - 2021-12-11,
 Uniqueness of a positive solution for the Laplace equation with indefinite superlinear boundary conditions: near a critical case, [[南大阪応用数学セミナー:https://sites.google.com/view/soams/2021]]. [[スライド:https://drive.google.com/file/d/1pSb_BnU6mplD5A2vABhRPfgP8A8iMYpe/view?usp=sharing]]
 
 //--------------------------------------
 
 - 2017-12-14, 
 concave-convex タイプの非線形楕円型境界値問題に対するループ型有界連続体解集合の存在について,変分問題セミナー(首都大学東京).
 
 /////////////////////
 - 2012-03-09, 
 // &COLOR(white,red){予定};
 ロジスティックタイプの非線形楕円型境界値問題に対する正値解の大域的分岐構造について,変分問題セミナー(首都大学東京).
 [[講演要旨:https://drive.google.com/file/d/1b-O0rSzb9AxN3JLApPskg4fdhov_Myv9/view?usp=sharing]]
 // &ref(12henbun-abst.pdf); 
 [[講演スライド:https://drive.google.com/file/d/1LSQSgbCXv5-C0gczehk75SXWf9lFg8Hy/view?usp=sharing]]
 // &ref(shutodai2012.pdf);
 
 /////////////
 - 2010-09-28, 
 '''Global bifurcation of positive solutions for some elliptic problems with nonlinear boundary conditions''', 洞爺解析セミナー(洞爺山水ホテル和風,北海道洞爺湖温泉町).[[講演スライド:https://drive.google.com/file/d/1y55fIXFsDuVJQ4u_RYfqxx2xBkUiYdK1/view?usp=sharing]] 
 //&ref(tohya2010.pdf);
 
 /////////////
 - 2007-09-10,
 '''Nehari manifolds, fibering maps and semilinear elliptic boundary value problems''', 数理科学セミナー(同志社大学工).
 
 /////////////
 - 2006-12-20, 
 '''Blowing-up principal eigenvalues of Neumann eigenvalue problems with indefinite weights''', 解析セミナー(筑波大学数学).
 
 /////////////
 - 2006-12-02, 
 ノイマン条件下における主固有値の爆発問題,応用解析研究会(早稲田大学理工).
 
 /////////////
 - 2006-09-10, 
 ノイマン条件のもとでの主固有値の爆発問題,数理科学セミナー(茨城大学教育).
 //&ref(FrontPage/note07_0404.pdf);
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