(with Georges Neaime, Gerhard Röhrle, Christian Stump) Oberseminar Arrangements and Symmetries, 2022-2023

(with Toshiyuki Akita and Masahiko Yoshinaga) Discrete Geometric Structure Seminar, 2017-2021

 Arrangements, Matroids and Logarithmic Vector Fields, Oberwolfach Research Institute for Mathematics, Germany, June 16-21, 2024

TBA, Groups and Geometry Seminar, Universität Bielefeld, Germany, July, 2024

Vines and MAT-labeled graphs, FPSAC, Ruhr-Universität Bochum,  Germany, July 22-26, 2024

Vines and MAT-labeled graphs, Hyperplane Arrangements 2023, Rikkyo University, Ikebukuro Campus, Japan, December 11-15, 2023

Vines and MAT-labelings, Workshop "Singularities, arrangements, and low-dim. topology" IV, JSPS-VAST Bilateral Joint Research Project, FPT University Quy Nhon, Vietnam, September 11-15, 2023

Inductive and divisional posets, Seminar of Department of Mathematics--Informatics, Da Lat University, Vietnam, August 30, 2023

Vines and MAT-labelings, Oberseminar zur Algebra und Algebraischen Kombinatorik, Leibniz Universität Hannover, Germany, June 8, 2023

A type $B$ analog of the Ish arrangement, Oberseminar zur Algebra und Algebraischen Kombinatorik, Leibniz Universität Hannover, Germany, May 25, 2023

A short introduction to arrangements of hyperplanes, A virtual math conference to celebrate  the 85th birthday of Prof. Moshe Rosenfeld, Vietnam, March 19, 2023

Old and new results on freeness properties of reflection arrangements, Spring School: Real, Complex, and Symplectic Reflection Groups, Ruhr-Universität Bochum,  Germany, March 6-10, 2023

Flag-accurate arrangements, Characteristic Polynomials of Hyperplane Arrangements and Ehrhart Polynomials of Convex Polytopes, RIMS, Kyoto University,  Japan, February 14-17, 2023

Flag-accurate arrangements, Workshop "Singularities, arrangements, and low-dim. topology" III, JSPS-VAST Bilateral Joint Research Project, Institute of Mathematics VAST, Vietnam, December 19-20, 2022

Arrangements arising from digraphs and freeness of arrangements between Shi and Ish, Arrangements in Ticino, USI-SUPSI campus East, Lugano-Viganello, Switzerland, June 27 - July 1, 2022

Hyperplane arrangements and Ehrhart theory, Combinatorial Coworkspace, Haus Bergkranz, Kleinwalsertal, Austria, March 19-27, 2022

Arrangements arising from digraphs and freeness of arrangements between Shi and Ish, Workshop "Singularities, arrangements, and low-dim. topology", JSPS-VAST Bilateral Joint Research Project, Japan-Vietnam, December 6-10, 2021 (Online)

Arrangements arising from digraphs and freeness of arrangements between Shi and Ish, Workshop on Commutative Algebra and Algebraic Geometry, Institute of Mathematics VAST, Vietnam, November 13-16, 2021 (Online)

Arrangements arising from digraphs and freeness of arrangements between Shi and Ish, Hoi nghi mot so chu de thoi su trong Toan hoc va Ung dung, VNU HUS and VIASM, Vietnam, October 30-31, 2021 (Online)

Period collapse in characteristic quasi-polynomials of integral hyperplane arrangements, Arrangements at Home IV: Geometry and Topology,  DTI-SUPSI, Switzerland, June 30 - July 2, 2021 (Online)

Some probabilistic interpretations of $G$-Tutte polynomial, Recent developments in arrangements, Japan, February 15-16, 2021 (Online)

Characteristic and Ehrhart quasi-polynomials for root systems, Logarithmic Vector Fields and Freeness of Divisors and Arrangements: New perspectives and applications, Oberwolfach Research Institute for Mathematics, Germany, January 24-30, 2021 (Online)

Eulerian polynomials for subarrangements of Weyl arrangements, Hội thảo Hình học-Giải tích (Workshop on Geometry and Analysis), Tam Dao, Vinh Phuc, Vietnam, September 27-29, 2019

Eulerian polynomial: A link between characteristic and Ehrhart quasi-polynomials, ミニシンポジウム 超平面配置  (Minisymposium on Hyperplane Arrangements), JCCA - DMIA - SGT, National Institute of Technology Miyakonojo College, Japan, August 27-29, 2019

Eulerian polynomials for subarrangements of Weyl arrangements, Hyperplane Arrangements in Wakkanai, Wakkanai Hokusei Gakuin University, Japan, August 21-23, 2019

Positivity of the coefficients of $G$-Tutte polynomials, Recent advances in matroids and Tutte polynomials, Hokkaido Summer Institute, Hokkaido University, Japan, July 22-26, 2019

Positivity of the coefficients of $G$-Tutte polynomials, New developments in matroid theory, SIAM Conference on Applied Algebraic Geometry, University of Bern, Switzerland, July 9-13, 2019

The exponents of $A_1^2$ restrictions of Weyl arrangements and Ehrhart theory, Arrangements at Western, Western University, Canada, May 21-31, 2019 (Slides)

A combinatorial description of the exponents of $A_1^2$ restrictions of Weyl arrangements, CIMPA - IMH Research School  Hyperplane Arrangements: recent advances and open problems, VAST, Vietnam, March 11-22, 2019

Characteristic quasi-polynomials and a connection to Ehrhart theory, The 15th Mathematics Conference for Young Researchers, Hokkaido University, Japan, March 4-7, 2019 

A combinatorial description of the exponents of $A_1^2$ restrictions of Weyl arrangements, On hyperplane arrangements, configuration spaces and related topics, Hokkaido University, Japan, February 20-22, 2019

Interpretations for characteristic quasi-polynomials via subspace and toric arrangements, The Second Vietnam Workshop on Graph Theory and Discrete Geometry, VIASM, Vietnam, January 9-13, 2019

Interpretations for characteristic quasi-polynomials via subspace and toric arrangements, The 6th Franco-Japanese-Vietnamese Symposium on Singularities (FJV2018), University of Khanh Hoa, Nha Trang, Vietnam, September 15-21, 2018 (Slides)

Characteristic quasi-polynomial and its applications to root systems, Matroids, Reflection Groups and Free Hyperplane Arrangements, RIMS, Kyoto University, Japan, June 11-15, 2018 (Slides)

$G$-Tutte polynomials via arithmetics, combinatorics and topology, AMS Spring Eastern Sectional Meeting, Special Session on Arrangements of Hypersurfaces, Northeastern University, USA, April 21-22, 2018

$G$-Tutte polynomial via algebraic combinatorics, topology and enumeration, The 14th Mathematics Conference for Young Researchers, Hokkaido University, Japan, February 27 - March 2, 2018

The largest coefficient of the highest root and the second exponent of the Weyl group, PISA-HOKKAIDO Summer School on Mathematics and Its Applications, The University of Pisa, Italy, August 30 - September 13, 2016 (Slides)

Characteristic quasi-polynomials of integral hyperplane arrangements, University of Bologna,  Italy,  Novemver 23 28 30, 2022 (Mini course) 

Multiple Addition Theorem, Seminar on Geometry and Topology, Institute of Mathematics VAST, Vietnam, January 20, 2022 (Online)

Characteristic and Ehrhart quasi-polynomials for root systems, Oberseminar of Institute of Algebra and Geometry, Otto-von-Guericke University Magdeburg, Germany, November 30, 2021

Arrangements arising from digraphs and freeness of arrangements between Shi and Ish, Vortrag im Oberseminar Arrangements and Symmetries, Ruhr-Universität Bochum,  Germany, July 19, 2021 (Online)

Characteristic quasi-polynomials of integral hyperplane arrangements, Vortrag im Oberseminar Arrangements and Symmetries, Ruhr-Universität Bochum,  Germany, May 3 10 17, 2021 (Online) (Lecture series)

Characteristic and Ehrhart quasi-polynomials for root systems, Osaka Combinatorics Seminar, Osaka University, Japan, January 16, 2021 (Online) (notes)

A brief introduction to hyperplane arrangements: combinatorics and enumeration, Algebraic Geometry Online Seminar, Da Lat University, Vietnam, June 13, 2020 (Online)

Quasi-polynomials in arrangement and Ehrhart theories, Handayama Seminar on Geometry & Algebra, Okayama University of Science, Japan, December 12, 2019 

The Addition-Deletion Theorems, Seminar on Hyperplane Arrangements, VAST, Vietnam, September 26, 2019

Characteristic quasi-polynomials and a connection to Ehrhart theory, Shinshu Topology Seminar, Shinshu University, Japan, November 15, 2018 

Plus-one generated hyperplane arrangements and Terao's deletion theorem, Seminar on Geometry and Topology, VAST, Vietnam, October 4, 2018

Abelian Lie group arrangements and $G$-Tutte polynomials, Problems around hyperplane arrangements, Discrete Geometric Structure Seminar, Hokkaido University, Japan, March 15, 2018

$G$-Tutte polynomial via arithmetics, combinatorics and topology, Joined seminar on Mathematics for Computer Science and Topology and Geometry, VAST, Vietnam, February 1, 2018 

The exponents of $A_1^k$ restrictions of Weyl arrangements, Seminar on Hyperplane Arrangements, VAST, Vietnam, March 9, 2017 (Slides)

The exponents of $A_1^k$ restrictions of Weyl arrangements, Seminar on Algebra-Geometry-Topology, VNU Hanoi University of Science, Vietnam, March 13, 2017 (Slides)

The second exponent of Weyl group is one plus the largest coefficient of the highest root, Seminar on Hyperplane Arrangements, VAST, Vietnam, February 25, 2016

Weighted Erdos-Mordell inequality for star-shaped polygons, Seminar on Computational Geometry, VAST, Vietnam, April 14, 2014 (Slides)

On $A_1^2$ restrictions of Weyl arrangements, Hyperplane Arrangements and Singularities (Hyper-JARCS), University of Tokyo, Japan, December 2-6, 2019 (PDF)

$G$-Tutte polynomials and application to topology of subgroup arrangements, Pusan National University-Hokkaido University Joint Symposium, Hokkaido University, Japan, December 2017 (PDF)

$G$-Tutte polynomials and application to topology of subgroup arrangements, The 5th Franco-Japanese-Vietnamese Symposium on Singularities (FJV2017), Kagoshima University, Japan, October 27 - November 3, 2017 (PDF)

The exponents of a certain restriction of Weyl arrangements, Topology of Singularity in honor of Mutsuo Oka on the occasion of his 70th birthday, VAST, Vietnam, February 20-22, 2017 (PDF)

The exponents of a certain restriction of Weyl arrangements, Summer Conference on Hyperplane Arrangements, Hokkaido University, Japan, August 8-12, 2016 (PDF)