Last modified December 25, 2023.
Talks outside Japan
 Tomoyoshi Ibukiyama,
Genus Character Lfunctions of Nonmaximal Quadratic Orders,
Academia Sinica, Taipei, November 17, 2023,
 Tomoyoshi Ibukiyama,
Dimensions of paramodular forms and algebraic modular forms with
involution,
Academia Sinica, Taipei, November 13, 2023,
 Tomoyoshi Ibukiyama,
Dimensions of paramodular forms with AtkinLehner sign,
Arithmetic, Geometry, Cryptography and Coding theory,
CIRM, Luminy, France, June 7, 2023,
 Tomoyoshi Ibukiyama,
Survey on quaternion hermitian lattices
and its application to supersingular abelian varieties.
, Arithmetic, Geometry, Cryptography and Coding theory,
CIRM, Luminy, France, June 1, 2021
 Tomoyoshi Ibukiyama,
Automorphic differential operators and special functions,
Sirius Mathematics Center conference "Integrable systems and
automorphic forms, February 25, 2020
 Tomoyoshi Ibukiyama,
A new pullback formula and a half integral version of Harder's
conjecture on congruences,
Oberwolfach workshop "Modular forms"
December 17, 2019
 Tomoyoshi Ibukiyama,
Algebraic modular forms of symplectic groups and Ihara lifts,
"Conference on the arithmetic theory of quadratic forms",
Jan. 9, 2019, Seoul National University, Korea.
 Tomoyoshi Ibukiyama, Supersingular abelian surfaces and polarizations,
November 14, 2018, Seminar of Academia Sinica, Taipei.
 Tomoyoshi Ibukiyama, Symplectic algebraic automorphic forms and Ihara lifts,
Nov. 12, 2018, National Taiwan Univ. Colloquium, Taipei.
 Tomoyoshi Ibukiyama, Explicit construction of theta series for any vectorvalued weight
and applications. May 31, 2018, American Univ. Beirut, Beirut, Lebanon.
 Tomoyoshi Ibukiyama, Quaternion hermitian lattices and supersingular abelian varieties,
May 9, May 16, 2018, Seminar of Wuhan Univ. Wuhan, China.
 Tomoyoshi Ibukiyama, Universal automorphic differential operators
and a theory of special functions, May 11, 2018,
Colloquium of Wuhan Univ. Wuhan, China.
 Tomoyoshi Ibukiyama, Universal automorphic differential operators
on Siegel modular forms, July 10, 2017,
"Aspects of automorphic forms and applications", University of Hong Kong, Hong Kong, China.
 Tomoyoshi Ibukiyama, Introduction to Siegel modular forms
and automorphic differential operators, June 9, June 14, June 19, 2017,
Shanghai Jiao Tong Univ. Shanghai, China.
 Tomoyoshi Ibukiyama, Siegel modular forms and Ihara lifts to algebraic modular forms, May 26, 2017,
"Modular forms are everywhere", MPI, Bonn, Germany
 Tomoyoshi Ibukiyama, Universal automorphic differential operators on Siegel modular forms,
March 25, 2017, JAMI 2017, Local zeta functions and the arithmetic of moduli spaces,
A conference in memory of JunIchi Igusa, Johns Hopkins Univ. Baltimore, USA.
 Tomoyoshi Ibukiyama, Introduction to Siegel modular forms and their construction.
February 22, 23, 2017, Seminar at Acadmia Sinica, Taipei.
 Tomoyoshi Ibukiyama, Conjectures on Siegel modular forms of halfintegral weight
and integral weight. February 20, 2017, Lakeside Seminar, Academia Sinica, Taipei.
 Tomoyoshi Ibukiyama, Modular forms on the compact symplectic group,
September 28, 2016, Seminar at Shanghai Jiao Tong University, Shanghai, China.
 Tomoyoshi Ibukiyama, Siegel modular forms and automorphic differential operators,
September 22 and 27, 2016, Seminar at Shanghai Tongji University, China.
 Tomoyoshi Ibukiyama, Conjecture on Shimura type correspondence of degree two and
Harder's conjecture, July 7, 2016, Automorphic forms on metaplectic groups and related topics,
IISER(Indian Institute of Science Education and Research), Pune, India
 Tomoyoshi Ibukiyama, Siegel modular forms and quaternion hermitian forms.
June 27, 2016, Arithmetic and low dimensional hyperbolic spaces,
Galatasaray Univ. Istanbul, Turkey.
 Tomoyoshi Ibukiyama, Higher spherical polynomials motivated by
differential operators on Siegel modular forms.
February 25, 2016, Colloquium Inst. Math, Academia Sinica, Taipei, Taiwan.
 Tomoyoshi Ibukiyama,
Quaternion hermitian forms and supersingular geometry (I) (II),
February 22, 24, 2016, NCTS Number Theory Seminar,
Academia Sinica, Taipei, Taiwan.
 Tomoyoshi Ibukiyama, The vanishing criterion of automorphic forms on
tube domains, January 21, 2016, Math. Forschungsinstitut Oberwolfach, Germany.
 Tomoyoshi Ibukiyama, The universal higher spherical series associated with
differential operators on Siegel modular forms,
ASARC Workshop on Coding theory and Number Theory,
January 13, 2016, Haeundae Riviera Hotel, Pusan, Korea.
 Tomoyoshi Ibukiyama, The universal differential operators on
Siegel modular forms, Number Theory Lunch Seminar, August 19, 2015, MPIM, Germany.
 Tomoyoshi Ibukiyama, The universal differential operators on
Siegel modular forms, July 30, 2015, Univ. Mannheim, Germany.
 Tomoyoshi Ibukiyama, New theorems on Jacobi forms of general degree,
Automorphic forms: Advances and Applications, May 25, 2015, CIRM, Luminy, France
 Tomoyoshi Ibukiyama, Higher Spherical Polynomials,
Algebraic Combinatorics Workshop, November 27, 2014, Univ. Science and Technology of China,
Hefei, China.
 Tomoyoshi Ibukiyama, Differential operators on Siegel modular forms and
applications, October 28, 2014, Tsinghua Univ. Seminar, Beijing, China.
 Tomoyoshi Ibukiyama, Construction of liftings to vector valued Siegel modular forms,
April 29, 2014, workshop in Oberwolfach, "Modular forms", organized by J. Bruinier, A. Ichino,
T. Ikeda, O. Immamoglu.
 Tomoyoshi Ibukiyama, Jacobi forms of degree two, December 18, 2013,
41st Seminar AachenKoelnLilleSiegen on Automorphic Forms at MPI in Bonn.
 Tomoyoshi Ibukiyama, Differential operators on Siegel modular forms and
applications, November 25, 2013, Oberseminar Zahlentheorie, Univ. Koln.
 Tomoyoshi Ibukiyama, Differential operators on Siegel modular forms and
various applications, November 8, 2013, Number Theory Seminars, ETH Zurich.
 Tomoyoshi Ibukiyama, A halfintegral weight version of Harder's conjecture on
congruences, September 25, 2013, Number Theory Lunch,
Max Planck Institute fuer Mathematik, Bonn, Germany.
 Tomoyoshi Ibukiyama, Differential operators on Siegel modular forms and its various
applications, September 16, 2013, Colloquium of Math. Department, Durham, UK
 Tomoyoshi Ibukiyama, Shimura type conjecture revisited, March 19, 2013,
Darmstadt, Germany.

Tomoyoshi Ibukiyama, Differential operators on Siegel modular forms,
Seminar at Shanghai Jiao Tong Univ.
November 16, 2012.

Tomoyoshi Ibukiyama, Dimensions of Siegel modular forms and related theories
Seminar at Shanghai Tongji University
November 15, 2012.
 Tomoyoshi Ibukiyama, Structure of Jacobi forms of degree two, Seminar
at Shanghai Tongji University, China, August 24, 2012.
 Tomoyoshi Ibukiyama, Higher spherical polynomials and holonomic
systems, at Shanghai Jiao Tong Univ., China, Main Session
of Conference on Algebraic Combinatorics Shanghai 2012, August 20,
2012.
 Tomoyoshi Ibukiyama, Exact critical values of a symmetric fourth L
function and Zagier's conjecture, The 26th automorphic workshop,
Vancouver, University of British Columbia, Vancouver, Canada, April 28, 2012.
 Tomoyoshi Ibukiyama, Several conjectures on liftings between Siegel
modular forms, International Workshop on Mathematics, New Developments
in Modern Number Theory and Applied Mathematics & Special
Contribution of Students and Elearning, GUtech, Muscut, Oman,
February 19, 2012
 Tomoyoshi Ibukiyama, Exact critical values of a symmetric fourth L
function and Zagier's conjecture, Invited talk in Arbeitstagung, Bonn, Germany,
June 25, 2011.
 Tomoyoshi Ibukiyama, Jacobi forms of degree two of index two, Conference
on "Explicit modular forms and application" in CIRM, Luminy
France, May 9, 2011.
 Tomoyoshi Ibukiyama, Trace formula of superspecial abelian varieties
with real multiplications, First Joint meeting of AMSSomachi (Sociedad
de Mathemática de Chile), Special Session: Arithmetic of Quadratic
Forms and Integral Lattices, Pucon, Chile, December 15, 2010
 T. Ibukiyama, Type numbers of quaternion hermitian lattices, quinary
lattices, and supersingular abelian varieties, December 17, 2009, Joint
meeting of KMS and AMS, Ewha Women Univ. Seoul, Korea.
 T. Ibukiyama, Supersingular abelian varieties and modular forms, June
7, 2009, Microsoft Research Institute, Redmond, WA. USA.
 Tomoyoshi Ibukiyama, Supersingular abelian varieties and modular
forms, March 7, 2009, HRI International Conference in Mathematics,
Harish Chandra Research Institute, Allahabad, India
 Tomoyoshi Ibukiyama, Differential operators on Siegel modular forms
and holonomic system, Conference on Codes, Invariants and Modular
Forms, and Oberseminar of Max Planck Instutut f&oumul;ur Mathematik, Bonn, Germany,
July 10, 2008
 Tomoyoshi Ibukiyama, Dimensions of Siegel Modular Forms, 22th Annual
Workshop on Automorphic Forms and Related Topics, March 10,
2008, at Blocker Hall, Texas A & M University, College Station, TX, USA.
 Tomoyoshi Ibukiyama, Siegel modular forms of small weight and Witt
operators, International Conference on The Algebraic and Arithmetic
Theory of Quadratic Forms 2007, December 13, 2007, Lake Llanquihue,
Puerto Montt, Chile
 Tomoyoshi Ibukiyama, Siegel modular forms of weight three and supersingular
abelian surfaces, Modular forms and Moduli spaces, Satellite
Meeting for Festival dedicated to 300th birthday of Leonhard EULER,
organized by V. Gritsenko, D. Orlov, P. Zograf. July 9, 2007, St.
Petersburg, Russia
 Tomoyoshi Ibukiyama, Taylor expansion of Jacobi forms of general degree,
Conference "Formes de Jacobi et applications" in CIRM Luminy
France, May 8, 2007
 Tomoyoshi Ibukiyama, Siegel modular forms of weight three and supersingular
abelian surfaces, March 14, 2007, Number Theory Lunch Seminar,
Max Planck Insitutut für Math.
 Tomoyoshi Ibukiyama, Dimension of Siegel Modular Forms, March,
2007, Univ. Rome "La Sapienza", Rome, Italy.
 Tomoyoshi Ibukiyama, Siegel modular forms of halfintegral weight and
conjectures on Shimura type correspondence and liftings, October 9,
2006, Conference "Modular Forms" at Schiermonnikoog, The Netherland,
organized by Gerald van der Geer, Bas Edixhoven and Ben Moonen.
 Tomoyoshi Ibukiyama, Siegel modular forms of small weights and conjectural
correspondence of Shimura or Langlands type, talk on September
8 in INdAM,WORKSHOP on Modular Forms, Automorphic Forms and Related Moduli Spaces
from September 5 to 9, 2005, organized by
R. Salvati Manni and van Geemen
 Tomoyoshi Ibukiyama, "Differential operators on Siegel modular forms,
special functions, and applications" The 19th annual workshop on automorphic
forms and related topics, Univ. North Texas, March 16 to
21, 2005.
 Tomoyoshi Ibukiyama, Conjecture of a Shimura correspondence for
Siegel Modular Forms of Degree Two, 14:0014:50, January 12, 2005.
Seminar AACHENKOELNLILLESIEGEN ON AUTOMORPHIC FORMS
 Tomoyoshi Ibukiyama, Oberwolfach Conference, Gitter und Anwendungen,
K. Saito's Conjecture on positivity of eta products and "extremal
pair" of lattices, January 7, 2005, Mathematiches Forschungsinstitut
Oberwolfach, Oberwolfach, Germany
 Tomoyoshi Ibukiyama A conjecture on Shimura correspondence between
vector valued Siegel modular forms of degree two, Number Theory
Conference in honour of Harold Stark, Minnesota, USA, August 7,
2004
 Tomoyoshi Ibukiyama, Explicit structures of Siegel modular forms and
differential operators, KIASPostech joint workshop on number theory
and modular forms, Seoul, Korea, Dec.6 , 2002.
 Tomoyoshi Ibukiyama, Dimensions of modular forms and zeta functions,
Number Theory Seminar of University of Wisconsin, Madison,
October 17, 2002
 Tomoyoshi Ibukiyama, Explicit structures of Siegel modular forms and
differential operators, AMS regional meeting at Madison, WI USA,
Special Session on Arithmetic Geometry, October 13, 2002.
 Tomoyoshi Ibukiyama, Explicit structures of Siegel modular forms and
differential operators, Arithmetique et Combinatoire, CIRM, Luminy,
France, September 26, 2002.
 Tomoyoshi Ibukiyama, Siegel modular forms of half integral weights
and a lifting conjecture, September 24, 2001, Conference "Formes de
Jacobi et applications" in CIRM Luminy France
 Tomoyoshi Ibukiyama, Siegel modular forms of half integral weights
and a lifting conjecture, Number Theory Seminar, Max Planck Institut
for Mathematics, February 21, 2001
 Tomoyoshi Ibukiyama, General theory of differential operators and construction
of Siegel modular forms, Reseaux et formes quadratiques,
conference in CIRM, France, September 2529, 2000
 Tomoyoshi Ibukiyama, Modular forms of rational weights and unitary
reflection groups, The 14th annual workshop on automorphic forms
and related topics, March 27, 2000, Boulder, Colorado, USA
 Modular forms of rational weights, Heidelberg Univ. Dec. 10, 1999
 On L functions of ternary zero forms, Yonsei Univ. Seoul, Korea, Jan. 6, 19
 Zeta functions of indefinite quadratic forms, Mini course in Number
Theory, Sogang University, Jan. 5, 6, 7, 8, 1999
 KoecherMaass series of Eisenstein series, Conference in Oberwolfach
institut, Modulformen mehrere variablen, December 7, 1998, with H.
Katsurada.
 KoecherMaass series of Siegel Eisenstein series, Number Theory Lunch,
Max Planck Institut für Mathematik, October 15, 1997.
 Differential operators on automorphic forms, harmonic polynomials,
and differential equations, Max Planck Institut für Mathematik, March
1997, Germany
 On zeta functions of prehomogeneous vector spaces related to dimension
formulae, Max Planck Institut Universität Mathematik, February 1997,
Germany
 On Koecher Maass series of Siegel Eisenstein series and related zeta
functions, Department of Math. Heidelberg Univ. December 1996,
Germany
 On a class of easy zeta functions related with dimension formula, Department
of Math. Mannheim Univ. December 1996, Germany
 Dimensions of automorphic forms and related zeta functions, Max
Planck Arbeitsgruppe Berlin : Geometrie u. Zahlen Theorie, November
1996, Germany
 International conference in Schloss Ringberg on abelian varieties,
RottachEgern, Germany (1987, July).
 International conference on modular forms,
Göttingen, Germany, (1987, July).
 International conference in Oberwolfach on modular forms of several
variables, organized by W. Baily Jr. and Klingen, Oberwolfach, Germany (1985, July)
 International conference on L^{2}cohomology in MaxPlanck institut
für Mathematik, Bonn, Germany (1984, March).
Talks in Japan
 Tomoyoshi Ibukiyama,
RankinCohen differential operators on Siegel modular forms and
applications,
Sendai spring conference on automorphic forms,
June 21, 2024.
 Tomoyoshi Ibukiyama,
Differential operators on automorphic forms, special functions, and
arithmetic applications,
The third Sendai miniworkshop on automorphic forms,
"Automorphic forms, Algebraic geometry, and (automorphic) differential operators,
February 4, 2024.
 Tomoyoshi Ibukiyama,
Dimension formulas of paramodular forms with involution,
RIMS workshop, January 24, 2024.
 Tomoyoshi Ibukiyama,
Genus character L functions of nonmaximal quadratic orders and adeles,
Autumn meeting of MSJ(Tohoku University）,
September 20, 2023.
 Tomoyoshi Ibukiyama,
Genus character L functions of nonmaximal quadratic orders and adeles,
Autumn meeting of MSJ(Tohoku University）,
September 20, 2023.
 Tomoyoshi Ibukiyama,
Differential operators on Siegel modular forms and Laplace transforms,
Spring meeting of MSJ(Chuo University）,
March 18, 2023.
 Tomoyoshi Ibukiyama,,
Dimensions of paramodular forms with involutions,
Spring meeting of MSJ（Chuo University）,
March 18, 2023.
 Tomoyoshi Ibukiyama,
Genus character $L$ functions of quadratic order
in an adelic way,
Arithmetic Seminar Day in Toyonaka,
March 13, 2023
 Tomoyoshi Ibukiyama,
Differential operators on Siegel modular forms and Laplace transforms,
RIMS workshop,
January 27, 2023
 Tomoyoshi Ibukiyama,
Supersingular loci of low dimensions and
parahoric subgroups
RIMS workshop
"Theory and applications of Supersingular curves and Supersingular
Abelian Varieties" October 13, 2020
 Tomoyoshi Ibukiyama,
Pullback formulas and applications,
January 24, 2020
Conference on "Analytic, geometric and padic aspects of
automorphic forms and Lfunctions"
RIMS, Kyoto
 Tomoyoshi Ibukiyama,
Supersingular abelian surfaces, automorphisms, and the trace formulas
October 4, 2019,
Conference on "Supersingular abelian varieties and related arithmetics"
at Nagoya univ.
 Tomoyoshi Ibukiyama,
A survey on polarizations of superspecial abelian varieties
and the field of definition,
September 30, 2019,
Conference on "Supersingular abelian varieties and related arithmetics"
at Nagoya univ.
 Tomoyoshi Ibukiyama,
A survey on quaternion hermitian lattices and
algebraic modular forms,
September 30, 2019,
Conference on "Supersingular abelian varieties and related arithmetics"
at Nagoya univ.
 Tomoyoshi Ibukiyama,
Graded rings of modular forms of rational weight,
March 11. 2019、Low dimensional topology and
number theory XI, Osaka Univ.
 Tomoyoshi Ibukiyama,
Automorphic differential operators and special polynomials,
Dec. 11. 2018、Study of algebraic combinatorics and related theory of group and algebra、
RIMS, Kyoto
 Tomoyoshi Ibukiyama,
Supersingular abelian varieties and arithmetic of
quaternion hermitian forms, Dec. 6, 2018, Tohoku Algebra Seminar,
Tohoku Univ.
 Tomoyoshi Ibukiyama,
Ihara lifts and conjectural correspondences between symplectic automorphic forms
of genus two. May 23, 2018,
RIMS workshop, Profinite Monodromy, Galois Representations,
and Complex Functions、RIMS, Kyoto.
 Tomoyoshi Ibukiyama, Siegel modular forms of middle parahoric subgroup and
Ihara lift, January 18, 2018, RIMS workshop,
Analytic and Arithmetic Theory of Automorphic Forms, RIMS, Kyoto.
 Tomoyoshi Ibukiyama, (1) Problem setting and first characterization
by invariant harmonic polynomials.(2) Two canonical bases of spherical polynomials.
(3) Inhomogeneous variables and holonomic systems.
(4) (i) Universal generating series and
universal automorphic differential operators.
(ii) Another oneline formula for special cases
September 3, 4, 5, 6, The 20th autumn workshop on number theory at Hakuba,
"Automorphic differential operators on Siegel modular forms"
Hotel Abest Happo Aldea (Hakuba village in Nagano prefecture.)
 Tomoyoshi Ibukiyama, Gtype numbers of quaternion hermitian lattices and
supersingular geometry.
February 9, 2017, RIMS workshop, Modular forms and related topics,
RIMS, Kyoto.
 Tomoyoshi Ibukiyama, Siegel's zeta functions of general indefinite
quadratic forms, "School of Mock Modular Forms and Related Topics"
IndustryUniversityGovernment Collaboration Innovation Plaza,Kyushu University,
November 24, 2016.
 Tomoyoshi Ibukiyama, The universal differential operators on
Siegel modular forms, Workshop at RIMS, Kyoto Univ.
Automorphic forms, Automorphic Lfunctions and related topics,
February 3, 2016.
 Tomoyoshi Ibukiyama, The universal differential operators on
Siegel modular forms, November 27, 2015, Number Theory Seminar at Waseda University
 T. Ibukiyama,
Siegel modular forms and computer calculations: personal experience,
results, and open problems,
Workshop on Computational Number Theory with Implementations 2015,
February 22, 2015.
 T. Ibukiyama, Three theorems on Jacobi forms of general degree,
RIMS workshop "Modular Forms and Automorphic Representations",
Kyoto Univ. February 2, 2015.
 T. Ibukiyama, Correspondence between symplectic automorphic forms,
Workshop on number theory of automorphic forms, Kumamoto univ.
January 8, 2015.

T. Ibukiyama, Jacobi forms of general degree,
The 17th Autumn Workshop on Number Theory,
Hakuba Highmount Hotel, November 9, 2014.

T. Ibukiyama, Construction of liftings to vector valued Siegel modular forms,
The 18th Joint Workshop on Number Theory, Waseda University, March 12, 2014.

T. Ibukiyama, Higher Spherical Polynomials (joint work with Don Zagier)
RIMS workshop, Automorphic Forms and Related Zeta Functions,
January 22, 2014.

T. Ibukiyama, Shimizu L function of quadratic orders, compsition and genus theory, and
trace formula, Waseda University Number Theory Seminar,
January 17, 2014.

T. Ibukiyama, Vector values Jacobi forms of degree two of index one,
Workshop on Modular Forms and Jacobi Forms,
Joetsu University of Education, June 11, 2013
 T. Ibukiyama, Structures of Vector Valued Jacobi Forms of Degree two and
Dimension Formulas, Seminar on Algebra, Ehime Univ.
April 22, 2013.

T. Ibukiyama, Differential operators on automorphic forms and the theory of classical groups,
Graduate School of Information Sciences, Colloquium of information mathematics,
February 20, 2013.

T. Ibukiyama, Structures and dimensions of
vector valued Jacobi forms, and conjectures of Shimura type and
Harder type, RIMS conference, Automorphic representations and related topics,
organized by Atsushi Ishino and Taku Ishii, January 25, 2013.

T. Ibukiyama, Differential operators on automorphic forms and their application,
Seminar on Number Theory in Waseda University, January 11, 2013.
 T. Ibukiyama, Shimura type and Harder type conjectures revisited,
liftings, dimensions and examples, The 15th Autumn Workshop on
Number Theory, November 2, 2012, at Hakuba Highmount Hotel.
 T. Ibukiyama, A lift to vector valued Siegel modular forms of halfintegral weight and
Conjectures of Shimura type revisited, General talk in the Algebra Section of the Autumn Meeting of Math. Soc. Japan
, September 18, 2012
 Differential operators on Siegel modular forms, Conference on Groups,
VOAs and Related Structures in Honor of Masahiko Miyamoto, at
Univ. Tsukuba, September 11, 2012.
 T. Ibukiyama, Conjectures on correspondence of Siegel Modular forms and Dimension Formulas,
Special Lecture for receiving the Award of Algebra in the Spring Meeting of Math. Soc. Japan, March 28, 2012.
 T. Ibukiyama and H. Katsurada, Exact critical values of the standard
Lfunctions of vector valued Siegel modular forms, January 19, 2012,
Workshop at RIMS Kyoto, "Study of automorphic forms and automorphic L functions".
 T. Ibukiyama, Exercises on Jordan algebras and tube domains (A vanishing
criterion on automorphic forms on symmetric tube domains) The
14th Autumn workshop on Number theory, Hakuba Highmount hotel,
Nov. 4, 2011
 T. Ibukiyama, SaitoKurokawa Lift 2, The 19th Summer School on Number Theory,
"Liftings", September 6, 2011, at FujiHakoneLand Schole Plaza Hotel,
 T. Ibukiyama, Exact critical values of the symmetric fourth L function
and Zagier's conjecture, Seminar on Number Theory and Automorphic Forms of Osaka University,
June 17, 2011
 T. Ibukiyama, Those days of the new discovery on zeta functions of prehomogeneous vector spaces, its past and future,
"Special meeting of thinking of Hitoshi Saito". October 2, 2010.
 T. Ibukiyama, EichlerSelberg Trace formula, September 7, 2010, The 18th Summer School on Number Theory,
"Introduction to ArthurSelberg trace formula", Yamanakaonsen KajikaSo Royal Hotel. /li>
 T. Ibukiyama, The Taylor expansion of Jacobi forms of general degree
and some application to explicit structures of higher indices, RIMS
conference at Univ. Tokyo, Automorphic Forms, automorphic representations,
and related topics, January 21, 2010, organized by M.
Tsuzuki
 T. Ibukiyama, Differential operators on Siegel modular forms as special
functions and applications, September 15, 2009, Geometry and Analysis
of Automorphic Forms of Several Variables (Oda kanreki), Univ.
Tokyo.
 T. Ibukiyama, Type numbers of quaternion hermitian lattices, quinary
quadratic forms and supersingular abelian varieties,
Workshop at RIMS, Kyoto, "Algebraic Number Theory and Related Topics", Dec. 11, 2008
 T. Ibukiyama SaitoKurokawa lifting and Jacobi forms of level N, Sep.
12, 2008, The 11th Autumn Workshop on Number Theory,
 T. Ibukiyama Towards explicit trace formulas, Sep. 6, 2008, Explicit
Structures in Modular Forms and Number Theory, Kinki Univ.
 T. Ibukiyama, Generating functions and holonomic system of orthogonal polynomials
of several variables consistint of invariant harmonic polynomials;
New several vaiable version of Gegenbauer polynomials", October 8, 2007 in
Workshop on study of accessary parameters 2, Kumamoto Univ. Organized by
Yoshishige. Haraoka.
 T. Ibukiyama, Dimension formulae of Siegel modular forms of weight
three and supersingular abelian surfaces, The 4th Spring Conference
on Modular Forms and Related Topics, "Siegel Modular Forms and
Abelian Varieties", February 6, 2007
 T. Ibukiyama, Paramodular Forms and Compact Twist: Dimensions
and Traces, The 9th Autumn Workshop on Number Theory, Hakuba,
organized by M. Furusawa, November 10, 2006.
 T. Ibukiyama, Siegel modular forms of halfintegral weight and conjectures
on Shimuratype correspondence and liftings, Conference on
Modular Forms, Schiermonnikoog in the Netherland, organized by G.
van der Geer, Bas Edixhoven, Ben Moonen. October 9, 2006
 T. Ibukiyama, Siegel modular forms of small weights and conjectural
correspondence of Shimura and Langlands type, February 20, 2006,
Conference on L function at Kyushu Univ. organized by Lin Weng and
Masanobu Kaneko
 T. Ibukiyama and N. P. Skoruppa, Jacobi forms of weight 1 and applications
to Siegel modular forms of critical weight, Workshop in RIMS, Study of
Automorphic Forms, L functions, Periods, January 24, 2006.
 T. Ibukiyama, Dimension formulas of automorphic forms, Conference in celebration of
Yasuo Morita's 60th birthday, November 22, 2005.
 T. Ibukiyama, Higher Spherical Polynomials and Functions, The Second
COE Workshop on Sphere Packings, at Kyushu Univ. May 31, 2005
 T. Kuzumaki and T. Ibukiyama, Differential operators from H_{2n} to
H_{n}×H_{n} and other explicit operators, The 7th Autumn Workshop on
Number Theory, "Differential operators on Siegel modular forms and
application", October 27, 2004.
 T. Ibukiyama, The 7th Autumn Workshop on Number Theory, "Differential
operators on Siegel modular forms and application", October
26, 2004.
 T. Ibukiyama, Holomorphic Differential operators on Siegel modular
forms, The 7th Autumn Workshop on Number Theory, "Differential
operators on Siegel modular forms and application", October 25, 2004.
 T> Ibukiyama, Various lifting conjectures on Siegel modular forms of degree two
and Shimura type correspondence, August 2, 2004, The 47th Symposium on Algebra,
Sendai International Center.
 T. Ibukiyama, K. Saito's conjecture eta products, Seminar on Complex geometry and mathematical physics, RIMS,
May 29, 2004.
 T. Ibukiyama, Construction of vector valued Siegel modular forms and conjectures on Shimura type correspondence,
Seminar on Number Theory, Department of mathematics, Faculty of Science, Hiroshima University,
May 14, 2004.
 T. Ibukiyama, Construction of vector valued Siegel modular forms and conjectures on Shimura type correspondence,
Annual meeting of Mathematical Society of Japan, March 28, 2004, General talk at Tsukuba Univ. in Algebra Section.
 Tomoyoshi Ibukiyama, Construction of Vector Valued Siegel Modular Forms and Shimura Correspondence,
The Third Spring Conference on Modular Forms and Related Topics, Curreac, Hamamatsu, Japan,
February 16, 2004.
 T. Ibukiyama, Formulation of conjectures on Shimura type correspondence of Siegel modular forms and examples of
cubic zeta liftings. Workshop in RIMS, Construction of automorphic forms and its application,
January 21, 2004.
 Tomoyoshi Ibukiyama, Graded rings of Siegel modular forms and differential
operators, Conference on Zeta Functions, Topology and Quantum
Phisics, Kinki University, 2003.3.6
 T. Ibukiyama, Application of modular forms to the theory of quadratic forms,
The 2nd Spring Conference on Automorphic Forms and Related Topics, February 15, 2003.
 T. Ibukiyama, Introduction to Siegel modular forms,
The 1st Spring Conference on Automorphic Forms and Related Topics,
"The Ring of Modular Forms", February 16, 2002.
 T. Ibukiyama, Vector valued Siegel modular forms of Sym(4) and Sym(6),
Workshop in RIMS, Study of Dirichlet series associated with automorphic forms,
January 30, 2002.
 Syuichi Hayashida and Tomoyoshi Ibukiyama, A lifting conjecture on
Siegel modular forms of half integral weights, September 11, 2001,
JapaneseGerman seminar on "Explicit structures of modular forms
and zeta functions" at Hakuba Highmount Hotel
(The 4th Hakuba conference), supported by JSPS and DFG.
 T. Ibukiyama, "Easy" zeta functions, The 9th Summer School on Number Theory,
July 19, 2001.
 T. Ibukiyama, Ring of modular forms of one variable of fractional weight,
Seminar on Number Theory, Kyoto Univ. May 11, 2001.
 T. Ibukiyama, Graded rings of modular forms of rational weights of level
11 and 13, Waseda University Symposium on Number Theory, March 12, 2001,
at Faculty of Science, Waseda Univ.
 T. Ibukiyama and S. Hayashida, A lifting conjecture on Siegel modular forms
of half integral weights and Jacobi forms, January 31, 2001, Miniconference on
Number Theory, at Machikaneyama Kaikan, Osaka University.
 T. Ibukiyama, Structures of vector valued Siegel modular forms and differential operators,
Workshop in RIMS, Algebraic Number Theory and Related Topics, December 19, 2000.
 Tomoyoshi Ibukiyama、A general theory of differential operators on
Siegel modular forms and special polynomials, Conference on codes, lattices,
modular forms and vertex operator algebras, Yamagata University October 3, 2000.
 T. Ibukiyama, On dimensions of automorphic forms of Tube domains,
THe 3rd Hakuba Autumn Workshop on Number Theory, Hakuba Highmount Hotel,
10, September, 2000.
 T. Ibukiyama, Modular forms of fractional weight,
The 8th Summer School on Number Theory, OumiHachiman Kokumin Kyukamura, July 12, 2000
 T. Ibukiyama and S. Hayashida, Siegel modular forms of half integral weights
and a lifting conjecture, Workshop at RIMS, Automorphic forms on algebraic groups,
automorphic representations and automorphic L functions, June 28, 2000.
 T. Ibukiyama, Modular forms of rational weights and modular varieties,
Waseda Seminar on Number Theory, Faculty of Science, Waseda University, June 9, 2000.
 T. Ibukiyama, Modular forms of rational weights,
Colloquium on Mathematical Sciences, Muroran Institute of Technology, March 8, 2000.
 T. Ibukiyama, Differential operators on automorphic forms, Miniconference
on modular forms, February 3, 2000.
 T. Ibukiyama, Modular forms of rational weights and unitary reflection
groups, Workshop at RIMS, Finite groups and algebraic combinatorics, January 18, 2000.
 T. Ibukiyama, Modular forms of fractional weight,
Seminar on number theory and automorphic forms, Osaka University, November 19, 1999.
 Tomoyoshi Ibukiyama, On dimensions of modular forms of symmetric
tube domains and zeta functions of prehomogeneous vecto spaces,
JapanFrance seminar on prehomogenous vector space, , November 11,
1999
 T. Ibukiyama, Classification and construction of exceptional Lie algebra over
algebraic number field. The 7th Summer School on Number Theory, "Number Theory of Algebraic Groups",
July 16, 1999.
 T. Ibukiyama, Concrete structres of Siegel modular forms of halfintegral weight,
The 7th workshop on algebraic combinatorics, June 25, 1999.
 T. Ibukiyama, Classification and construction of exceptional Lie algebras,
Preparatory meeting of the 7th Summer School on number theory,
March 9, 1999, Kanazawa Univ.
 T. Ibukiyama, Zeta functions of indefinite quadratic forms,
Special Lecture on Number Theory, Kyoto University, February 19, 1999.
 T. Ibukiyama, Explicit description of zeta functions of indefinite quadratic
forms, Conference on algebraic combinatorics and combinatorial theory of
quadratic forms, November, 1998, Yamagata Univ.
 T. Ibukiyama, Proofs of functional equations of Koecher Maass series and
indication to converse theorem,
The 1st Hakuba autumn workshop on number theory "Study of Koecher Maass series"
September 10, 1998, Hakuba Hightmount Hotel.
 T. Ibukiyama, Autumorphic forms of tube domains and symmetric cones,
 T. Ibukiyama, On formally real Jordan algebras,
The 1st Hakuba autumn workshop on Number Theory "Study of Koecher Maass series",
September 10, 1998, Hakuba Highmount Hotel.
 T. Ibukiyama, Existence theorem of algebraic curve of genus 3
with maximum numbers of rational points over the finite field
Fp_{2} (p: any odd prime)、
THe 2nd conference on Algebraic Geometry, Number Theory, and Code/Cryptography,
July 27, 1998. Univ. Tokyo.
 T. Ibukiyama and H. Katsurada, KoecherMaass Dirichlet series for Eisenstein
series of Klingen type, Workshop at RIMS, "Number Theory and Automorphic Forms"
January 30, 1998.
 T. Ibukiyama, Explicit description of Siegel modular forms of half integral
weights and dimension formula, Workshop on prehomogeneous vector spaces and related topics,
Rikkyo University, January 14, 1998.
 T. Ibukiyama and F. Onodera, Paramodular forms of level 2,
Autumn meeting of Math. Soc. Japan, general talk, October 1, 1997, Univ. Tokyo.
 T. Ibukiyama, Proof of SaitoKurokawa lifting due to DukeImamoglu,
The 5th Summer School on Number Theory, July, 1997, Yamanashi Prefecture Seifuso Annex, July 1997
 T. Ibukiyama, On Shintani's zeta functions of ternary zero forms (third
approach), Workshop at RIMS "Study of prehomogeneous vector spaces", April 1996.
 T. Ibukiyama and H. Katsurada, An explicit form of KoecherMaass Dirichlet
series associated with Siegel Eisenstein series, Annual meeting of Math. Soc. Japan, general talk,
April 1996, Niigata University
 T. Ibukiyama and H. Katsurada, An explicit form of KoecherMaass Dirichlet
series associated with Siegel Eisenstein series, Workshop at RIMS,
Automorphic forms on algebraic groups, November 1995
 T. Ibukiyama, Dimension formulas of automorphic forms of symmetric domains of type IV,
Workshop on automorphic forms on Sp(2;R) and SU(2; 2),
January 1995.
 T. Ibukiyama, On dimensions of automrophic forms and zeta functions
of prehomogeneous vector space, Workshop at RIMS "Study of prehomogeneous vector spaces", October 1994.
 T. Ibukiyama, An explicit formula for zeta functions associated with
quadratic forms, Workshop at RIMS "Study of prehomogeneous vector spaces", October 1994.
 T. Ibukiyama, Around dimension formulas of automorphic forms and zeta functions,
The 39th Symposium on Algebra, July 1994, Ehime University
 T. Ibukiyama and H. Saito, On zeta functions associated to symmetric matrices、
Special Lecture in Algebra section of the annual meeting of Math. Soc. Japan, April 1994, Kobe University.
 T. Ibukiyama, On some elementary exponential sums, Waseda workshop on number theory,
March 1994, Waseda Univ.
 T. Ibukiyama and H. Saito, Conjectures on dimensions of Siegel modular forms of degree n,
Annual meeting of Math. Soc. Japan, general talk, March 1993, Chuo Univ.
 T. Ibukiyama and H. Saito, Explicit forms of Shintani zeta functions,
Annual meeting of Japan Math. Soc. general talk, March 1993, Chuo Univ.
 T. Ibukiyama, Introduction to quadratic forms (II) (Indefinite quadratic forms and Eisenstein series) ,
The 1st Summer School on Number Theory, July 1993, Waseda University Seminar House.
 T. Ibukiyama and H. Saito, On zeta functions of symmetric matrices and
dimensions of Siegel modular forms, Workshop at RIMS " Study of automorphic forms and L functions",
November 1992.
 T. Ibukiyama, On differential operators on automrophic forms and invariant
pluriharmonic polynomials, Workshop at RIMS "Study of automorphic forms and related zeta functions"
January, 1992.
 T. Ibukiyama, An Arithmetic theory of supersingular abelian varieties,
Workshop at RIMS "Einstein metric and YangMills connection (The third period of geometry of quaternions)",
March 1991.
 T. Ibukiyama, Arithmetic theory of supersingular abelian varieties,
"Symposium on Algebraic Geometry", Osaka University, March 1991.
 T. Ibukiyama, Parahoric subgroups and automorphic forms,
Workshop at RIMS "Algebraic groups and related topics" May 1990.
 T. Ibukiyama, Supersingular abelian varieties and rational points of
algebraic curves, Workshop at RIMS "Number Theory and study related to automorphic forms", December 1989.
 T. Ibukiyama, Dimensions of automorphic forms and vanishing of contribution of unipotent conjugacy classes,
Workshop at RIMS "Automorphic forms and related topics", January, 1987.
 T. Ibukiyama, Jacobi forms and Siegel modular forms of half integral weight,
Workshop on Number Theory, Kyushu University, February 1986.
 T. Ibukiyama, Automorphism groups of lattices and a generalization of trace formula,
Workshop at RIMS, Study of Automorphic representation, November 1985.
 T. Ibukiyama and K. Hashimoto, Comparison of dimensions of
automorphic forms of Sp(2;R) and Sp(2),
Simposium on automorphic forms, RIMS, Kyoto Univ. October 1984.
 T. Ibukiyama, Langlands correspondence between automorphic forms, in particular
the case of symplectic groups. October 18, 1984, Special Talk at autumn meeting of
Math. Soc. Japan, Tokyo University.
 T. Ibukiyama, Conjectures on correspondence of symplectic automorphic forms,
Autumn meeting of Mathematical Society Japan, general talk,
October 8, 1981, Yamaguchi Univ.
 T. Ibukiyama, On symplectic Euler factors of genus two,
Workshop at RIMS, Kyoto, "Theta functions, Siegel modular forms and related topics", June, 1981.
 T. Ibukiyama, On Siegel modular forms, Overall conference, February, 1980, Nagoya University.
 T. Ibukiyama and K. Hashimoto, On class numbers of positive definite binary
quaternion hermitian forms, The 25th Symposium on Algebra, August, 1979 at Hokkaido Univ.
 T. Ibukiyama, a talk in the annual meeting of MSJ, Spring, 1979(details lost)
 T. Ibukiyama, Maximal orders of definite quaternion algebras, April 4, 1978,
Annual meeting of Math. Soc. Japan at Nagoya Univ.
 T. Ibukiyama, On CM type variety of modular type, April 6, 1977,
Spring meeting of Math. Soc. Japan, general talk in Algebra section at Kyoto Univ.
 T. Ibukiyama, Formal groups and L functions, Workshop in RIMS, March, 1973.
Organization of meetings

Conference on "Supersingular Abelian Varieties and Related Arithmetics",
with Shigeyuki Kondo(Nagoya) and Toshiyuki Katsura(Tokyo),
September 30 to October 4, 2019,
Nagoya University,

The 20th Hakuba Number Theory Workshop,
"Automorphic differential operators on Siegel modular forms",
September 3 to 7, 2017,
Hotel Abest Happo Aldea (Hakuba Village, Nagano Prefecture),

JAMI 2017 Conference,
Local zeta functions and the arithmetic of moduli spaces:
A conference in memory of JunIchi Igusa
March 2226, 2017,
Johns Hopkins University, coorganized with
Margaret Robinson, David Savitt(USA) and
Tatuso Kimura, Tetsuji Shioda(JAPAN), and Program committee:
Valery Alexeev, Richard Hain, Francois Loeser.

School on Mock Modular Forms and Related Topics,
November 21 to 25, 2016,
Kyushu University IndustryUniversityGovernment Collaboration Innovation Plaza,
(organized with Masanobu Kaneko and Kazuhiro Hikami).

Explicit Theory of Automorphic Forms,
March 23, 2014 to March 28, 2014,
Shanghai Tongji University, Shanghai
(organized with Hongwen Lu, Nils Peter Skoruppa and Haigang Zhou).

International workshop on Mathematics,
New Developments in Modern Number Theory and Applied
Mathematics & Special Contribution of Students and Elearning,
18 Feb. 2012  22 Feb. 2012,
GUtech, Muscut, Oman,
(Scientific Committee member), (Main organizer is B. Heim).

The 14th Autumn Workshop on Number Theory,
October 31 to November 5, 2011, Hakuba highmount hotel, Hakuba, Japan,
(organized with Takao Watanabe).

The 11th Autumn Workshop on Number Theory,
Hakuba highmount hotel, Hakuba, Japan, September 11 to 15, 2008
(organized with Tamotsu Ikeda)

Oberwolfach Conference, Modul Formen,
Mathematisches Forschungsinstitut Oberwolfach, Oberwolfach, Germany,
(With Winfried Kohnen and S. Boecherer )
October 29 to November 2, 2007.

The 4th Spring Conference on modular forms and related topics,
"Siegel Modular Forms and Abelian Varieties",
February 59, 2007,
Hotel Curreac, Hamana Lake, Hamamatsu, Japan.

The seventh autumn workshop on number theory,
"Differential operators on Siegel modular forms and
application",
October 2430, 2004.
Hakuba Highmount Hotel, Hakuba, Japan.

Automorphic Forms and Zeta Functions, in Memory of Tsuneo Arakawa,
organized by S. Boecherer, T. Ibukiyama, M. Kaneko, F. Sato,
September 47, 2004, Rikkyo Univ. Tokyo, Japan.

The third Spring conference on modular forms and related topics,
2004.2.16  2004.2.20,
Organizers: T. Ibukiyama(Main organizer), K. Saito, E. Bannai,
M. Miyamoto, Hotel Curreac, HamanaLake, Hamamatsu, Japan.

Miniconference on Number Theory,
April 17 to 18, 2003, Osaka University, Japan.

The 2nd Spring conference on automorphic forms and related areas,
February 15 to 19, Curreac Hamana Lake, Hamamatsu, Japan,
(Main organizer with coorganizers Eiichi Bannai, Masahiko Miyamoto, Kyoji Saito）

Oberwolfach Conference, September 15 to 21, 2002,
Mathematisches Forshungsinstitut Oberwolfach, Overwolfach, Germany,
（cochairman with Siegfried Boecherer, Winfried Kohnen)

The 1st Spring conference on automorphic forms and related areas, "Rings of modular forms"
February 16 to 20, 2002, Curreac Hamana Lake, Hamamatsu, Japan,
(Main organizer with coorganizers Eiichi Bannai, Masahiko Miyamoto, Kyoji Saito).

Japan German seminar supported by JSPS (The 4th Autumn Workshop on Number Theory)
September 9 to 15, 2001, Hakuba highmount hotel (coorganizer with W. Kohnen), Hakuba, Japan.

Miniconference on number theory,
January 30 to 31, 2001, Osaka University, Japan,
(cochairman with Takao Watanabe)

The 3rd Autumn Workshop on Number Theory,
"Dimension formulas of automorphic forms"
September 9 to 13, 2000, Hakuba highmount hotel, Hakuba, Japan.

Mini conference on automorphic forms,
February 2 to 3, 2000, Osaka University, Japan.

The 2nd Autumn Workshop on Number Theory, "Eisenstein series",
September 10 to 14, 1999, Hakuba highmount hotel, Hakuba, Japan.

Oberwolfach conference,
Modulformen mehrerer variablen. Mathematisches Forschungsinstitut Oberwolfach, Oberwolfach, Germany,
December 6 to 11, 1998 (cochairman with W. Kohnen and S. Boecherer)

The 1st Autumn Workshop on Number Theory,
"Koecher Maass series", Hakuba highmount hotel, Hakuba, Japan,
September 10 to 14, 1998.

Conference on Modular forms and Modular Varieties, Osaka University, Japan
January 22 to 24, 1996.

The 1st Summer School on Number Theory,
"Eisenstein series", Seminar House of Waseda University, ShinanoOiwake, Japan,
July 18 to 21, 1993

RIMS workshop, "Study of Automorphic forms and L functions",
RIMS, Kyoto Univ. Japan, November 16 to 20, 1992
 Conference on Geometry and Automorphic Forms, February 22 to 26, 1988, Tohoku Univ. Japan
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