1.  Oberwolfach Research Institute for Mathematics (Arbeitsgemeinschaft: Combinatorial Hodge Theory), Germany 🇩🇪 (October 12 - 17, 2025), host: Chris Eur, June Huh, Matt Larson   

2.  Shanghai Center for Mathematical Sciences, Shanghai, China 🇨🇳 (September 14 - 19, 2025), host: Hehui Wu

3.  Shanghai Center for Mathematical Sciences, Shanghai, China 🇨🇳 (April 10 - 18, 2025), host: Jorge Olivares-Vinales

4.  Seoul National University, Seoul, Korea 🇰🇷 (March 10 - 14, 2025), host: Seok Hyeong Lee

5.  The University of British Columbia, Vancouver, Canada 🇨🇦 (November 25 - December 5, 2024), host: Jozsef Solymosi

6.  Sorbonne University, Paris, France 🇫🇷 (October 7 - October 24, 2024), host: Karim Adiprasito

7.  Shanghai Center for Mathematical Sciences, Shanghai, China 🇨🇳 (June 5 - 11, 2024), host: Jorge Olivares-Vinales

8.  Ulsan National Institute of Science and Technology, Ulsan, South Korea 🇰🇷 (December 28 - 30, 2023), host: Jinjoo Yoo

9.  Gwangju Institute of Science and Technology, Gwangju, South Korea 🇰🇷  (October 30 - November 5, 2023), host: Minki Kim

10.  University of Copenhagen, Copenhagen, Denmark 🇩🇰 (July 3 - September 30, 2023), host: Karim Adiprasito 

11.  Vietnam Institute for Advanced Study in Mathematics, Hanoi 🇻🇳 (July 15 - 23, 2023), host: Thang Pham

12.  University of Rochester, Rochester, NY, USA 🇺🇸 (May 21 - 27, 2022), host: Jonathan Pakianathan

Photos

All photos below were taken by me at the places I’ve visited.

2026

1.  Colloquium, Hanyang University, Korea 🇰🇷 (June 4, 2026) invited by Jinwook Jung 

 Title: An invitation to arithmetic combinatorics: Multiplicative decompositions of shifted subgroups in finite fields (1 hour)

2025

1.  International Youth Forum 2025, East China Normal University, online 🇨🇳 (December 8, 2025) 

 Title: When finite fields meet combinatorics (40 min) 

2.  BK Rookies Workshop 2025, Konjiam Resort, Gwangju, Korea 🇰🇷 (November 6, 2025) invited by Uhi Rinn Suh

Title: An invitation to additive combinatorics: Point-sphere incidences over finite fields (35 min)

3.  ECOPRO Paper Reading Seminar, IBS 🇰🇷 (October 29, 2025) invited by Hong Liu 

Title: Sphere intersections and incidences over finite fields (1 hour)

4.  SCMS Combinatorics Seminar, Shanghai Center for Mathematical Sciences, Shanghai, China 🇨🇳 (September 18, 2025) invited by Huhei Wu

Title: Recent progress on Diophantine tuples over finite fields (1 hour)

5.  Combinatorics Seminar, East China Normal University, Shanghai, China 🇨🇳 (September 17, 2025) invited by Longtu Yuan

Title: Recent progress on Diophantine tuples over finite fields (1 hour)

6.  Combinatorics and Graph Theory Seminar, Shanghai Jiao Tong University, Shanghai, China 🇨🇳 (September 16, 2025) invited by Xiaodong Zhang

Title: Recent progress on Diophantine tuples over finite fields (1 hour)

7.  BIRS Workshop - Finite Geometry and Extremal Combinatorics, Institute for Advanced Study in Mathematics (IASM), Hangzhou, China 🇨🇳 (June 27, 2025) invited by Hong Liu 

Title: Quasi-random hypergraphs arising from multivariate polynomials and their applications to Diophantine sets (55 min)

8.  Discrete Analysis at Yonsei (DAYS) workshop, Yonsei University, Seoul, Korea 🇰🇷 (June 19, 2025) invited by Joonkyung Lee 

Title: A construction of pseudorandom graphs for off-diagonal Ramsey numbers (50 min)

9.  CanaDAM 2025 - Finite fields and finite geometry, Ottawa, Canada 🇨🇦 (May 23, 2025) invited by Chi Hoi Yip 

Title: Diophantine tuples over finite fields (25 min)

10.  KSIAM, Konkuk University, Seoul, Korea 🇰🇷 (May 16, 2025) invited by Hayan Nam

Title: Diophantine tuples over finite fields (20 min)

11.  2025 KMS Spring Meeting, KAIST, Daejeon, Korea 🇰🇷 (April 25, 2025) 

Title: Combinatorics of unimodal maps (20 min)

2024

  1.  Discrete Math Seminar, University of British Columbia, Vancouver, Canada 🇨🇦 (December 3, 2024) invited by Jozsef Solymosi 

Title: A q-analogue of the binomial coefficient from orthogonal groups and its applications to off-diagonal Ramsey numbers (1 hour)

  2.  2024 DIMAG Internal Workshop, Lahan hotel Jeonju, Korea 🇰🇷 (November 19, 2024)

Title: Lower bounds for the clique number of Diophantine graphs (15 min)

  3.  Workshop on Topology and Combinatorics, IBS, Deajeon, Korea 🇰🇷 (November 11, 2024)

Title: The Charney-Davis conjecture and its related complexes (survey) (30 min)

  4.  2024 Algebraic and Analytic Structures on Manifolds and their Applications, The K Hotel Gyeongju, Korea 🇰🇷 (September 26-28, 2024) invited by Eunjeong Lee

Title: When finite fields meet combinatorics (2 hours)

  5.  2024 Korean Student Combinatorics Workshop, Gongju Hanok Village, Korea 🇰🇷 (July 29, 2024) invited by Donggyu Kim 

Title:  A postdoc life in Korea (1 hour)

  6.  2024 IBS-DIMAG workshop on combinatorics and geometric measure theory, Daejeon, Korea 🇰🇷 (July 18, 2024) 

 Title: Improved upper bounds for the largest size of Diophantine m-tuples (30 min) 

  7.  Summit:280, Budapest, Hungary 🇭🇺 (July 8, 2024)  

Title: Paley-like quasi-random graphs arising from polynomials (20 min)

  8.  Discrete Math Seminar, IBS DIMAG 🇰🇷 (June 18, 2024) invited by Sang-il Oum

Title: Paley-like quasi-random graphs arising from polynomials (1 hour)

  9.  Rookies Pitch, Seoul National University 🇰🇷 (June 4, 2024) invited by Uhi Rinn Suh  

Title: When finite fields meet combinatorics (30 min)

 10.  Discrete Analysis Seminar, Yonsei University, Seoul 🇰🇷 (May 7, 2024) (1 hour) invited by Jaeseong Oh  

Title: Paley-like quasi-random graphs arising from polynomials (1 hour)

 11.  Special Lecture, Korea University, Seoul 🇰🇷 (May 3, 2024) invited by Sangjib Kim 

Title: An Invitation to Spectral Graph Theory: Expander mixing lemma (75 min)

 12.  2024 KMS Spring Meeting, Daejeon Convention Center, Korea 🇰🇷 (April 19, 2024) 

Title: Improved upper bounds for the largest size of Diophantine m-tuples (20 min)

 13.  Combinatorics Seminar, Yeungnam University, Korea 🇰🇷 (February 20, 2024) invited by Jihye Park 

Title: Improved upper bounds of the largest size of generalized Diophantine m-tuples (30 min)

 14.  Workshop on Combinatorial Geometry, University of Miami, Florida 🇺🇸  (January 31, 2024)

Title: A q-analogue of the binomial coefficient from orthogonal groups (30 min)

 15.  Discrete Math Seminar, Online, University of British Columbia, Canada 🇨🇦 (January 24, 2024) invited by Joshua Zahl

Title: Intersection patterns and incidence theorems (1 hour)

2023

  1.  2023 KSIAM Annual Meeting, Special Session: Geometric and Topological Combinatorics, Kimdaejung Convention Center, Gwangju, Korea 🇰🇷 (November 4, 2023) invited by Minki Kim

Title: Orientable triangulable manifolds are essentially quasigroups (20 min)

  2.  Colloquium, Chonnam National University, Korea 🇰🇷 (October 30, 2023) invited by Bokhee Im 

Title: A construction of orientable triangulable manifolds from quasigroups (1 hour)

  3.  Developments in Combinatorics, Grand Hyatt Jeju, Korea 🇰🇷 (October 21, 2023) invited by Hong Liu

Title: Geometry of nondegenerate spaces over finite fields (15 min)

  4.  Algebra and Logic Seminar, Online, University of Denver 🇺🇸 (October 13th, Friday 2023) invited by Charlotte Aten 

Title: Improved upper bounds of the size of generalized Diophantine tuples (1 hour)

  5.  Finite Geometry & Friends - A Brussels Summer School on Finite Geometry, Vrije Universiteit Brussel, Belgium 🇧🇪 (September 18, 2023)

Title: Combinatorics of Euclidean spaces over finite fields (20 min)

  6.  The Korea-Taiwan-Vietnam Joint Meeting on Discrete Geometry and Geometric Measure Theory, Vietnam Institute for Advanced Study in Mathematics, Hanoi, Vietnam 🇻🇳 (July 18th, 2023) invited by Thang Pham

Title: Intersection patterns and incidence theorems (25 min)

  7.  2023 KMS Spring Meeting, Special Session: Extremal Combinatorics: Methods and Applications, Daejeon Convention Center, Korea 🇰🇷 (April 28th, 2023) invited by Nika Salia

Title: Intersection patterns and incidence theorems (20 min)

  8.  2023 KMS Spring Meeting, Special Session: Combinatorics of Symmetric Functions, Daejeon Convention Center, Korea 🇰🇷 (April 28th, 2023) invited by Meesue Yoo

Title: Modules of the 0-Hecke algebra for genomic Schur functions (20 min)

  9.  Unist 수리과학부 Seminar, Online, Unist 🇰🇷 (February 13th,14th,15th, 2023) invited by Wan Lee

Title: (1) Classification of nondegenerate quadratic forms over finite fields (2) The size of spheres over finite fields (3) An invitation for spectral graph theory - Expander mixing lemma (3 hours)

2022

  1.  Workshop on Algebras with Related Topics, Jeju National University, Korea 🇰🇷 (November 4th, 2022) invited by Boran Kim

Title: Modules of the 0-Hecke algebra for genomic Schur functions (1 hour)

  2.  2022 DIMAG and ECOPRO Internal Workshop, Utop Marina Hotel, Yeosu, Korea 🇰🇷 (October 31st, 2022) invited by Sang-il Oum

Title: Lower bounds for off-diagonal Ramsey numbers (20 min)

  3.  Korea-Taiwan-Vietnam joint Seminar in Combinatorics and Analysis, Online 🇻🇳 (October 28th, 2022) invited by Thang Pham

Title: Weak Bruhat interval modules of the 0-Hecke algebras for genomic Schur functions (1 hour)

  4.  Topology and Combinatorics Seminar at Ajou University, Online 🇰🇷 (October 6th, 2022) invited by JiSun Huh

Title: Weak Bruhat interval modules of the 0-Hecke algebras for genomic Schur functions (1 hour)

  5.  Public Presentation, Online, Sejong Academy of Science and Arts, 🇰🇷 (high school) (July 7th, 2022) invited by Yeochan Lee

Title: Binomial coefficients : beyond counting (이항계수: 경우의 수를 넘어서) (90 min)

  6.  2022 KWMS The 17th International Conference, Algebra Session,  KIAS 🇰🇷 (June 23, 2022)

Title: Modules of the 0-Hecke algebra for genomic Schur functions (20 min)

  7.  Colloquium, Online, Korea University 🇰🇷 (March 25, 2022) invited by Ya-Ryong Heo

Title: Combinatorics of Euclidean spaces over finite fields (1 hour)

  8.  The 24th KIAS Combinatorics Workshop, Shilla Stay Haeundae, Busan, Korea 🇰🇷 (February 23, 2022) invited by Seok-Jin Kim

Title: Threshold functions for some geometric incidence configurations in finite vector spaces (40 min)

  9.  KAIST Combinatorics Lab. Workshop 2022.02, St. John's Hotel, Gangneung, Korea 🇰🇷 (February 09, 2022) invited by Jang Soo Kim

Title: Combinatorics of Euclidean spaces over finite fields (50 min)

 10.  2022 Workshop on Algebra at Sono Belle, Sono Belle Cheonan, KIAS 🇰🇷 (January 16, 2022)

Title: Combinatorics of Euclidean spaces over finite fields (40 min)

2021

  1.  2021 Combinatorics Workshop, The Bloomvista, Yangpyeong, IBS Discrete Mathematics Group 🇰🇷 (December 21, 2021)

Title: Combinatorics of Euclidean spaces over finite fields (25 min)

  2.  One day Workshop, KIAS 🇰🇷 (December 15, 2021)

Title: Threshold functions for some geometric configurations in finite vector spaces (30 min)

  3.  2021 DIMAG Internal Workshop, St. John's Hotel, Gangneung, Korea 🇰🇷 (November 15-17, 2021) invited by Sang-il Oum

Title: Euclidean Kneser graphs (20 min)

  4.  Discrete Math Seminar, IBS DIMAG, Daejeon, Korea 🇰🇷 (July 20, 2021)  invited by Sang-il Oum

Title: Combinatorics of Euclidean spaces over finite fields (1 hour)

  5.  Combinatorial Algebraic Geometry - Geometry and Combinatorics from Root Systems, Online, ICERM 🇺🇸  (March 23, 2021)

Title: Combinatorics of quadratic spaces over finite fields (10 min)

  6.  CombinaTexas 2020/21, Online, Texas A&M University 🇺🇸  (February 20, 2021)

Title: A combinatorial correspondence between finite Euclidean geometries and symmetric subsets of Z/nZ (20 min)

  7.  Number Theory Seminar, Online, University of California, Irvine 🇺🇸  (January 14, 2021) invited by Nathan Kaplan

Title: An isometric invariant of quadratic spaces over finite fields (1 hour)

2020

  1.  Combinatorics Seminar, Online, University of Copenhagen 🇩🇰 (November 12, 2020) invited by Karim Adiprasito

Title: Combinatorics of quadratic spaces over finite fields (90 min)

  2.  Combinatorics Seminar, Online, University of Rochester 🇺🇸  (November 5, 2020) invited by Alex Iosevich

Title: Combinatorics of quadratic spaces over finite fields (1 hour)

  3.  Graduate Student Workshop on Representation Theory and Combinatorics, Online, Sogang University 🇰🇷 (September 17, 2020) invited by Young-Hun Kim

Title: Combinatorics of quadratic spaces over finite fields (1 hour)

  4.  AlCoVE: an Algebraic Combinatorics Virtual Expedition, Online 🇺🇸  (June 16, 2020) (Poster presentation)

Title: Combinatorics of quadratic spaces over finite fields (1 hour)

  5.  Graduate Online Combinatorics Colloquium, Online 🇺🇸  (April 15, 2020)

Title: Combinatorics of quadratic spaces over finite fields (1 hour)

2019

  1.  Binghamton University Graduate Conference in Algebra and Topology, Binghamton University, New York 🇺🇸  (November 2, 2019)

Title: An isometric invariant of combinatorial type of quadratic spaces over finite fields (30 min)

  2.  7th annual Mississippi Discrete Math Workshop, University of Mississippi, Oxford 🇺🇸  (October 27, 2019)

Title: The dot-binomial coefficients (25 min)

  3.  Facets of Algebraic Geometry (for Fulton's 80th), University of Michigan, Ann Arbor 🇺🇸  (October 18, 2019) picture

Title: Combinatorics of quadratic spaces over finite fields (5 min)