- Y. Choie, “Various aspects of Kronecker series”, Women in Automorphic forms, 20210920 -20210922, Organized by Claudia Alfes, Anke Pohl, Anna v. Pippich, Bielefeld University, Germany
- Y. Choie, “Kronecker series and Modular forms”, Number Theory Lunch Seminar, Max Planck Institute, Bonn, in honor of the 70th birthday of Professor Don Zagier, June 30, 2021
- Y. Choie, TBA, The international seminar on Automorphic Forms, Germany, 2021.06.22 (0nline), Organized by Yingkun Li (TU Darmstadt) and Markus Schwagenscheidt(ETH Zurich)
- Y. Choie, Period polynomials and Automorphic forms, Invited talk at Algebra session in 2021 Spring Korean Mathematical Society Annual Meeting, April 29-April 30, 2021 (online)
- Y. Choie, a Generating function of periods of modular forms, Heilbronn Number Theory seminar, U of Bristol, 2021 03 10 (online)
- Y. Choie, Modular form and Period polynomial, Joint Mathematics Meetings AMS Special Session, Quadratic forms and Theta functions, January 6, 2021 (online): Title: Modular forms and Period polynomials
- Y. Choie, Genernatinf functions of Periods of modular forms, the workshop on Transfer Operators in Number Theory and Quantum Chaos, HIM, Bonn 20200203-20200207
- Y. Choie, Kernels for Products of L-functions, Inaugural France-Korea Conference on Algebraic geometry, Number Theory, and Partial Differential equations, Institute of Mathematics, University of Bordeaux, France, .2019.11.24-2019.11.27.
- Y. Choie, Kernels for Products of Hilbert L-functions, Recent Advances and Applications of Modular forms, AMS meeting at the University of Hawaii Manea, March 22(3:30-3:50 20 min invited talk) , March 22-24, 2019.
- Y. Choie, Automorphic forms and Cohomology (invited talk 50 min), Special Session on “Recent developments in Automorphic forms”, AMS meeting at the University of Hawaii Manea, March 24 (9:00-9:50), March 22-24, 2019.
- Y. Choie, Modular form and cohomology, Automorphic forms on reductive groups and their covers: a conference in honor of Solomon Friedberg, ETH Zurich, 20180626-20180628.
- Y. Choie (Scientific committee member), Pan Asia Number Theory Conference 2018(25 – 29 Jun 2018), National University of Singapore, Singapore, Scientific Committee member.
- Y. Choie, Schubert Eisenstein Series, Lunch seminar, MPIM, Bonn, 20150204.
- Y. Choie, Visiting University of Hawaii (P. Guerzhoy), 20180501-2018051.
- Y. Choie, Visiting Stanford University (D. Bump) 20180511-20180514.
- Y. Choie, Visiting University of Maryland, (L. Washington), 201804066-20180422.
- Y. Choie, Visiting Hausdorff Mathematical Institute, 20180302-30180317.
- Y. Choie, Recent progress on Schubert Eisenstein series, Colloquium Talk, 2017 NCTS (Taiwan)-POSTECH (Korea) Joint Workshop on Number Theory, Inst. of Math. Academia Sinica, Taipei, Taiwan, Dec. 27 – Dec. 29 , 2017.
- Y. Choie, Modular forms and Cohomology, Recent trend in Number Theory, National Institute of Mathematical Science, Korea, Dec 19-Dec 22, 2017
- Y. Choie, a vital role of Automorphic forms in Number theory, Plenary speaker, 61st Annual Meeting of the Australian Mathematical Society Dates and Venue: Tuesday–Friday 12–15 December 2017 Venue: Macquarie University, North Ryde, Sydney, Australia
- Y. Choie, a vital role of automorphic forms in Number Theory, 2017 Da-San conference, Dec 1, Korean Mathematical Society, Busan, Korea
- Y. Choie, Various aspects of multiple zeta functions, Conference in Honor of Kohji Matsumoto’s 60th Birthday, Nagoya University, Japan, Aug 21-25, 2017
- Y. Choie, Schubert Eisenstein series, Aspects on Automorphic forms and Applications, University of Hong Kong, Hong Kong, 20170710-20170712.
- Y. Choie, Modular forms and Cohomology, Arithmetics on Automorphic forms, HIT, Harbin, 20170627-20170630
- Y. Choie, Modular forms and Cohomology, Arithmetics on Automorphic forms, HIT, Harbin, 20170627-20170630
- Y. Choie, Period of modular forms on $\Gamma_0(N)$ and Jacobi theta series, The Whittaker functions, Banff, Canada 20160724-20160729
- Y. Choie, Period of modular forms on $\Gamma_0(N)$ and Jacobi theta series, PANT2016 , Taipei, Taiwan, 20160712-20160715
- Y. Choie, Period of modular forms on $\Gamma_0(N)$ and Jacobi theta series, The second French-Korea Conference, U. of Bordeaux, France, 20160704-20160712
- Y. Choie, L-function (Euler to Langlands), Dept of Mathematics, HIT(Harbin Institute of Technology) , June 21, 23, 2016(visiting 20160617-20160628) (120 min $\times$ 2)
- Y. Choie, Period of modular forms on $\Gamma_0(N)$ and Jacobi theta series, 2016 PMI-NCTS Workshop-Number Theory, POSTECH, Pohang, Korea, June 4-8, 2016 (40 mits)
- Y. Choie, Multiple Period integrals and Cohomology, PMI International Workshop (25 mits), May 18-20, 2016
- Y. Choie, Schubert Eisenstein series and Demazure character, PMI workshop, POSTECH, 20150501
- Y. Choie, Schubert Eisenstein Series, Dept of Math, Number Theory Seminar, Utrecht University, 20150210
- Y. Choie, Schubert Eisenstein Series, Lunch seminar, MPIM, Bonn, 20150204
- Y. Choie, Schubert Eisenstein series, NCTS-PMI Joint workshop, Shinju, Taiwan 20141221-20141223
- Y. Choie, Three lectures on Periods of modular forms and related topics, Winter School on modular forms in one and several variables,20141211-20141213, Organized by Institute of Mathematical Sciences, Goa University
- Y. Choie, Schubert Eisenstein series, Number Theory Seminar, Columbia University, 20141118
- Y. Choie, Multiple Hecke L values, Analytic Number Theory and its applications:a
- conference in honor of Jeff Hoffstein conference. Greece, 20140707
- Y. Choie, An explicit bound for the first sign change of the Fourier coefficients of a Siegel modular form of genus $n$, Applications of Automorphic forms in number theory, to honor of Winnie Li, Louisiana, 20140412-20140415
- Y.Choie, Kronecker limit formula and Schubert Eisenstein Series, Number Theory Festival to honor of Prof Koo, 2014 0222, KAIST
- Y. Choie, Multiple Hecke L series, Automorphic forms, and their applications, to honor of the 60th birthday of Prof R. Murty, Chennai, India, Dec 8-13, 2013(50 mit)
- Y. Choie, On the Fourier coefficient of elliptic cusp forms, Automorphic forms, Combinatorial Representation and Multiple Dirichlet series, ICERM, Brown University, USA 20130415-20130421 (50 mit)
- Y. Choie, Schubert Eisenstein series, Workshop on Automorphic forms (Kohnen’s 60th birthday conference), University of Heidelberg, Germany 20130315-20130320 (50min )
- Y. Choie, Schubert Eisenstein Series, Combinatorics, Multiple Dirichlet series and Analytic Number Theory, ICERM, Brown University, USA 20130129
- Y. Choie, Siegel modular form mod $p$, Number Theory workshop(60 min), Knopp memorial workshop, Philadelphia, Temple University, USA, 20121110-20121112
- Y. Choie, Stume type bound of Siegel modular form mod $p$(60 min), CUNY Number Theory Seminar, NY, USA, 20121109 (G. Chinta)
- Y. Choie, Schubert Eisenstein series(50 min talk), Analytic Number Theory workshop, RIMS, Kyoto, 20121029-20121031(60 min)
- Y. Choie, “Non-vanishing of twisted Hecke L-function of level $1$”, Special Lecture, Nagoya University, 20121024-20121028 (150 min)
- Y. Choie, Schubert Eisenstein series(60 min talk), Automorphic forms and Combinatorics workshop, to honor of Prof. Bump, Stanford University, USA, 20120813-20120816 (60 min)
- Y. Choie, A Century-old mathematical problem, General Talk, the 9th International workshop of Korean Women Mathematical Society, Ewha Womens University, Seoul, Korea, 20120621-20120622 (50 min)
- Y. Choie, Schubert Eisenstein series, Nanyang Technology University, Singapore 20120618 (60 min)
- Y.Choie, $4 $ Lectures on “Jacobi forms and its applications”, Workshop on Modular forms and related topics, American University of Beirut, Beirut 20120206-20120210 (6 hour)
- Y.Choie, “Schubert Eisenstein Series”, NCTS, Taiwan-PMI, POSTECH, Korea (40 min talk) 20110724-20110726
- Y. Choie, “Mock modular forms”, NCTS, Taiwan, Number Theory Seminar (2-hour talk) 20110706
- Y.Choie, “Non-vanishing of twisted Hecke L-function of level $1$”, Automorphic form”, Max Planck Institute, Mathematics, Bonn, Number Theory Lunch Seminar(1 hour talk), 20110323
- Y.Choie, “Harmonic weak Maass forms and mock modular forms”, Number Theory Seminar, U. of Cambridge, 20110222 (visiting U Cambridge: 20110221-20110224)
- Y. Choie, “Non-vanishing of twisted Hecke L-function of level $1$, Automorphic form “, Invited Speaker(50 min), Pan Asia Number Theory, RIMS, Kyoto, Japan, 20100913-20100917
- Y. Choie, “Non-vanishing of twisted Hecke L-function of level $1$, Automorphic form” workshop(50 mint), NCTS(National Center for Theoretical Science) Taiwan 20100707-20100709
- Y. Choie, 4 Lectures on Quasi modular forms, Besse Summer School, France, 201006
- Y. Choie, Symmetric tensor power representation associated to modular form, Special session in Algebraic geometry and Number theory, The First China-Korea Mathematical Society Meeting, Chongqing, China 20100517-20100522
- Y. Choie, Quasimodular forms, KMS Spring Meeting 2010, April 24-25, ChungAnm University, Daejun, Korea
- Y. Choie, Quasimodulr forms, Automorphic form workshop, University of Hawai, Honolulu, USA 20100322-20100328
- Y.Choie, IAS, Princeton, Visitor 20100124-20100207, Analytic Number Theory Special year
- Y. Choie, Quasimodular forms(40 mits talk), Korea-Japan Number Theory, Seoul National University, 20100120-2010012
- Y. Choie, Eichler cohomology of automorphic forms revisited-Preliminary Survey talk, The first POSTECH-Taiwan workshop-Number Theory, POSTECH-BSRI 2009 Special year program, POSTECH 20091219-20091220
- Y. Choie, Not quiet modular, Plenary talk(50 mints), AMS-KMS joint meeting, Seoul, Korea, 20091212-20091220
- Y. Choie, Quasimodular forms and Their arithmetic properties, Invited Talk(40 minutes), International Conference on Analytic Number Theory, The birth centenary of Dr. Homi Bhabha, TIFR (Tata Institute of Fundamental Research), Mumbai, India, 20091005-20091009
- Y. Choie, Period relations of Jacobi forms, Mock functions and applications in combinatorics, Algebraic geometry, and mathematical physics, MPI, Germany 20090526-20090529
- Y. Choie, Quasi modular forms and Jacobi forms, POSTECH-Kyushu Workshop, Number Theory, and Related Topics, POSTECH, Pohang, Korea 20090106 (Main Organizer)
- Y. Choie, Quasimodular forms, 1-hour talk, Multiple Dirichlet series and Applications to Automorphic forms, ICMS, U. of Edinburgh 20080804-20080808
- Y. Choie, “Quasimodular forms”, Number Theory Seminar at Temple University, Philadelphia, USA, 20080403
- Y. Choie, ” Brou\’e-Enguehard maps and Atkin-Lehner involution”, Invited Talk, The fourth Korea-Japan Workshop on Algebra and Combinatorics, Pohang Korea 20080201-20080202
- Y. Choie, “Eichler Integral and More”, Invited Talk, East Asia Number Theory Conference, KAIST, DaeJun, 20080121-20080124
- Y. Choie, “Periods of Modular forms”, Lie Algebra, to honor of 70th birthday of Prof CH Myung, KIAS, Korea 20070730-20070801
- Y.Choie, “The first sign change of Fourier coefficients of cusp forms “, KIAS-POSETCH-SNU International Number Theory workshop, KIAS, Seoul, Korea, 20061207-20061209
- Y.Choie, Invited Talk, The 3rd International Workshop for Korean Women in Mathematics, Korea University, Seoul, Korea 20060626-20060627
- Y.Choie, Invited Talk, Modular forms of negative weight, KIAS Number Theory workshop, Invited talk, KIAS, Seoul, Korea: KIAS Number Theory Conference Commemorating 10th anniversary of the foundation of KIAS, Seoul, Korea, 20060619-20060622
- Y.Choie, Modular forms of Negative weight, Modular forms and related topics, to honor of 73rd birthday of M. Knopp, Philadelphia, USA January 20060109-20060110
- Y.Choie, Cryptosystem using hyperelliptic curves of genus $2$, Invited Talk, Fourier Institute, Grenoble, France, Oct 29/05.
- Y.Choie, The weight independent congruence relations of modular forms, Invited Talk, Fourier Institute, Grenoble, France, Oct 12/05.
- Y.Choie, Codes, Invariants and Modular forms, Semina, INRIA, France, Aug 24, 2005.
- Y.Choie, The weight independent congruence relations of modular forms, Invited Talk, University of Illinois, Urbana Champaign, July 22, 2005.
- Y.Choie, The weight independent congruence relations of modular forms, Invited Talk, University of Heidelberg, May 25, 2005.
- Y.Choie, Codes, Invariant and Modular forms, (London Mathematical Society Visiting Lecturer) Nottingham University, England, Seminar talk, Oct 22, 2004.
- Y.Choie, Codes, Invariant and Modular forms, (London Mathematical Society Visiting Lecturer) University of Sheffield, England, Seminar talk Oct 19, 2004.
- Y.Choie, Codes, Invariants and Modular forms, ( London Mathematical Society Visiting Lecturer) Cambridge University, England, Seminar talk Oct 19, 2004
- Y.Choie, Modular forms, Invariant and Theta identities, q-series conference, KIAS, Seoul, May 22, 2004.
- Y.Choie, Values of L-functions, 18th Annual Workshop on Automorphic Forms and Related Topics, Santa Babara, U.S.A., 20040320-20040326
- Y.Choie, Simple proof of Theta transformation formula, Workshop on Modular forms and related topics, Japan, Feb , 2004
- Y.Choie, Modular forms, Invariant and Codes, Plenary invited talk(50 min), The second East Asian conference in Algebra and Combinatorics, Kyusu University, Japan, Nov 17-21, 2003.
- Y.Choie, HK.Kim and J.Choi, Analytic Number Theory Informal Summer 2003 workshop, August 19, 2003, POSTECH; H.Kim, Regular Polytope Numbers and related research topics; J.Choi: Euler Numbers Y.Choie : About L-functions.
- Y.Choie, Two talks on CBMS Lecture series, Title: “Differential operators and Modular forms” and “Codes and Modular forms” , University of Illinois, Urbana (Invited speakers: K.Ono, Burnier, W.Kohnen, R.Mumty) 20030603-20030608
- Y.Choie, About L-functions, Number Theory-Algebra Camp, KAIST 2003, January 11-15
- Y.Choie, Invariance and Number Theory, KAIST Math Colloquium, Dec. 12/2002
- Y.Choie, Elliptic Curve Cryptosystem, ITRC, Bukyung University, June, 2002.
- Y. Choie, Jacobi forms and Codes, Number Theory Seminar, University of California, Santa Babara, January 22, 2002 (visiting January 21-27, 2002).
- Y. Choie, Codes and Modular forms, Invited talk In Applied Math. The session, KMS Annual meeting, Fall, 2001.10, Ewha Womens University 200110\\
- Y.Choie, Speeding up hyperelliptic cryptosystem, Mathematics in Public key cryptosystem, KIAS, June 25-27, 2001.
- Y. Choie, ” Modular forms and Their applications”, Invited talk, Millenium Number Theory Conference, University of Illinois, Urbana-Champaign, Chicago, USA 20000521-20000527
- Y. Choie, “Differential operators on Siegel modular forms”, NumberTheory Seminar, Organized by D.Goldfeld, Colombia University, Feb.21, 2000.\\
- Y. Choie, Number Theory and Code, Colloquium, ChungNam University, Nov. 29, 1999.
- Y. Choie, Special values of Koecher-Maass series of Siegel modular forms, Automorphic forms workshop, Organized by Ibukiyama, Hakuba, Japan, Sep, 1999.
- Y. Choie, Automorphic form workshop, Invited Speaker, Differential operators and Siegel forms,
- Y. Choie, Algebraic combinatorics and combinatorial quadratic forms, International Conference, organized by M. Ozeki, E. Bannai and M. Harada, Invited Speaker, Yamagata University, Japan, Nov. 12-19.
- Y. Choie, “Jacobi forms and periods of elliptic modular forms”, International Conference on Number theory and its related topics, Yonsei University, Seoul, Korea, Oct.20-Oct.22, 19981020-19981022
- Y. Choie, “Elliptic modular forms and Codes”, Symposium on Number Theory and its application, organized by Prof. Jong An Park, KangWoon University, Chuncheon, Korea, Sep. 12, 1998,
- Y. Choie, Non-linear differential equations for Jacobi forms, a talk by Hae-Sook Kim, Korean Mathematical Society, Spring Meeting, April 1998.
- Y. Choie, On Cryptosystems, Number Theory Seminar, April 11, 1998, Seoul National University, Seoul, Korea.\\
- Y. Choie, Differential operators and Siegel forms, Number Theory Seminar, Jan. 31, 1998, Kobe University, Japan (Invited by Prof. T. Yamazaki and Murase)
- Y. Choie, Differential operators and Jacobi forms, RIMS Automorphic forms and Number Theory Conference, RIMS, Jan. 26-Jan.30, Kyoto, Japan 19980126-19980130.
- Y. Choie, Differential operators and Siegel forms, KIAS Number Theory Conference, Dec.8-Dec.12, 1997, KIAS, Seoul, Korea.
- Y. Choie, Differential operators and Forms, The 3rd Korea-Japan Joint Seminar, 1997 July22-July24, POSTECH, Pohang, Korea
- Y. Choie, Rankin-Cohen brackets on Jacobi forms and Siegel forms of genus 2, Colloquium in Universite of Bordeaux, June(27), 1997.
- Y. Choie, Colloquium in Dept. of Math at POSTECH, March, 1997.
- Y. Choie, Jacobi forms and heat operator, Colloquium in Dept. of Math. at Univ. of Heidelberg, Heidelberg, Germany, June 1996.
- Y. Choie, Jacobi forms and heat operator, Colloquium in Dept. of Math. at Univ. of Cambridge, Cambridge, England, March 1996.