#New_accepted_paper *J. Pascal Gollin*, *Kevin Hendrey*, Hao Huang, *Tony Huynh*, Bojan Mohar, *Sang-il Oum*, Ningyuan Yang, Wei-Hsuan Yu, and Xuding Zhu, Sharing tea on a graph, Comb. Theory, accepted, 2026. arxiv.org/abs/2405.15353

J. Pascal Gollin gave a talk on the existence of a balanced separator dominated by small number of vertices in a graph excluding a wheel as an induced minor at the Discrete Math Seminar On June 9, 2026, J. Pascal Gollin from University of Primorska gave a talk at the Discrete Math Seminar on the…

#New_arXiv_paper Maria Chudnovsky, Linda Cook, James Davies, *Seokbeom Kim*, and *Sang-il Oum*, On the chromatic number of the union of comparability graphs, 2026. arxiv.org/abs/2606.09415

#New_accepted_paper Matthew Baker, Changxin Ding, and *Donggyu Kim*, The Jacobian of a regular orthogonal matroid and torsor structures on spanning quasi-trees of ribbon graphs, Adv. Math., accepted, 2026. arxiv.org/abs/2501.08796

Maria Chudnovsky gave a talk on bounding treewidth of n-vertex graphs excluding fixed induced minors as a function of n at the Discrete Math Seminar On June 2, 2026, Maria Chudnovsky from Princeton University gave a talk on bounding treewidth of n-vertex graphs excluding fixed induced minors as a…

#New_arXiv_paper Seewoo Lee, Byung-Hak Hwang, Hyojae Lim, Jihoon Hyun, *Ilkyoo Choi*, Yeachan Park, Jineon Baek, Hyukpyo Hong, Keewoo Lee, Jaeseong Heo, Hyungryul Baik, Chul-hee Lee, and Kyu-Hwan Lee, Lean-GAP: A Dataset of Formalized Graduate Algebra Problems, 2026. arxiv.org/abs/2606.02588

A year ago, few people in math took AI very seriously. Since then, everything has changed. AI has gone from being considered bad at simple arithmetic to helping solve increasingly abstract open problems. Tune in to The Quanta Podcast: podcasts.apple.com/us/podcast/t...

Fernanda Rivera Omaña gave a talk on the Erdős-Pósa property for matroid minors at the Discrete Math Seminar On May 26, 2026, Fernanda Rivera Omaña from the University of Waterloo gave a talk at the Discrete Math Seminar on the Erdős-Pósa property for matroid minors. The title of her talk was…

#New_published_paper Archontia C. Giannopoulou and *Sebastian Wiederrecht*, Two disjoint alternating paths in bipartite graphs: conformal crosses, Combinatorica, 46:19, May 2026. doi.org/10.1007/s004...

구글 deepmind에서 올린 논문 “Advancing Mathematics Research with AI-Driven Formal Proof Search” 못 푸는 문제도 많지만 풀리는 경우 미해결 문제 하나 풀고 lean으로 formal proof 완성하는데까지 수백달러 정도 쓰면 된다고. arxiv.org/abs/2605.227...

Xavier Goaoc gave a talk on a tree decomposition of the chirotopes of a planar point set and its application to counting triangulations at the Discrete Math Seminar On May 19, 2026, Xavier Goaoc from Université de Lorraine gave a talk at the Discrete Math Seminar on a tree decomposition of the…

2024, 2025년에 이어 2026년에도 2026 조합론 및 알고리듬 여름학교가 열립니다. 강연자 - Daniel Dadush: Algorithms & Geometry of Linear Programming - Magnus Wahlström: Matroids, delta-matroids, and applications 장소: KAIST 등록마감 5월 31일 기간: 8월 10일-14일 combialgo.dimag.kr/2026/

Welcome Arnaud Patey, a new graduate student of the IBS Discrete Mathematics Group The IBS Discrete Mathematics Group welcomes Arnaud Patey, a new graduate student of the Discrete Mathematics Group from May 18, 2026 to July 17, 2026. He is a MS student at ENS Rennes.

#New_arXiv_paper Dario Cavallaro, *Maximilian Gorsky*, Stephan Kreutzer, Dimitrios M. Thilikos, and Sebastian Wiederrecht, Optimal Bounds for the k-Disjoint Paths Problem, 2026. arxiv.org/abs/2605.14902

#New_arXiv_paper *Mujin Choi*, Tuukka Korhonen, and *Sang-il Oum*, Branch-width of represented matroids in matrix multiplication time, 2026. arxiv.org/abs/2605.14428

Benjamin Duhamel gave a talk on characterizing forests F such that forbidding a biclique and an induced minor isomorphic to F implies bounded path-width at the Discrete Math Seminar On May 12, 2026, Benjamin Duhamel from ENS de Lyon gave a talk at the Discrete Math Seminar on characterizing…

점심 먹고 커피 마시다가 대학원생들에게 Claude와 codex로 10분만에 논문 latex 파일만 보고 latex으로 한 시간 세미나 발표할 슬라이드 만드는 거 보여주었더니 다들 Codex 설치하러 갔습니다.

#New_arXiv_paper Tung H. Nguyen and *Sang-il Oum*, Ramsey-type χ-bounds for χ-bounded graph classes, 2026. arxiv.org/abs/2605.08848

#New_arXiv_paper *Maximilian Gorsky*, Kevin Hendrey, and *Tony Huynh*, The Erdős-Pósa property for prime-length cycles fails (and beyond), 2026. arxiv.org/abs/2605.04938

#New_accepted_paper Katie Clinch, Dániel Garamvölgyi, John Haslegrave, Tony Huynh, Jan Legerský, and Anthony Nixon, Stable cuts, NAC-colourings and flexible realisations of graphs, J. Graph Theory, accepted, 2026. arxiv.org/abs/2412.16018

Maximilian Gorsky gave a talk on a new algorithm for k-disjoint paths problem with an explicit running time at the Discrete Math Seminar On May 6, 2026, Maximilian Gorsky from the IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on a new algorithm for k-disjoint paths…

#New_arXiv_paper *Ilkyoo Choi*, Hojin Chu, Ringi Kim, and Boram Park, Existence of cycles of length divisible by 3 or 4, 2026. arxiv.org/abs/2605.02731

IBS Extremal Combinatorics and Probability Group (ECOPRO) in Daejeon, South Korea invites applications for research positions. Hiring up to 4 senior researchers. Deadline: June 10, 2026, 16:00 KST www.mathjobs.org/jobs/list/28...

Xin Wei gave a talk on the maximum size of a t-perfect hash family over an alphabet of size q at the Discrete Math Seminar On April 28, 2026, Xin Wei (魏歆) from the IBS Extremal Combinatorics and Probability Group gave a talk at the Discrete Math Seminar on the maximum size of a t-perfect hash…

#New_accepted_paper Konrad K. Dabrowski, François Dross, Jisu Jeong, Mamadou Moustapha Kanté, *O-joung Kwon*, *Sang-il Oum*, and Daniël Paulusma, Computing pivot-minors, Algorithmica, accepted, 2026. arxiv.org/abs/2311.04656

How can you tell two knots apart? It’s a tougher question than you might think. www.quantamagazine.org/a-powerful-n...

#New_arXiv_paper *Andreas Holmsen*, Attila Jung, Balázs Keszegh, Dániel G. Simon, and Gábor Tardos, Piercing all maximum cliques in hypergraphs, 2026. arxiv.org/abs/2604.21588

#New_accepted_conference_paper *Colin Geniet*, Fatemeh Ghasemi, and Mamadou Moustapha Kanté, Transducing Linear Decompositions of Tournaments, In the Proceedings of ICALP 2026 (Royal Holloway, University of London. London, UK, July 7-10), accepted, 2026. arxiv.org/abs/2601.02999

#New_arXiv_paper Édouard Bonnet, Yeonsu Chang, Julien Duron, *Colin Geniet*, and *O-joung Kwon*, Moderately beyond clique-width: reduced component max-leaf and related parameters, 2026. arxiv.org/abs/2604.19138

#New_accepted_conference_paper Édouard Bonnet, *Colin Geniet*, *Eun Jung Kim*, and Sungmin Moon, Fast shortest path in graphs with sparse signed tree models and applications, ICALP 2026 (Royal Holloway, University of London. London, UK, July 7-10), accepted, 2026. arxiv.org/abs/2602.06516

#New_accepted_conference_paper *Maximilian Gorsky*, Evangelos Protopapas and Sebastian Wiederrecht, Quickly excluding an annotated planar graph, In the Proceedings of ICALP 2026 (Royal Holloway, University of London. London, UK, July 7-10), accepted, 2026.

#New_accepted_conference_paper *Maximilian Gorsky*, Michał Seweryn, and Sebastian Wiederrecht, The price of homogeneity is polynomial, In the Proceedings of ICALP 2026 (Royal Holloway, University of London. London, UK, July 7-10), accepted, 2026.

#New_accepted_conference_paper *Mujin Choi*, *Maximilian Gorsky*, *Gunwoo Kim*, Caleb McFarland, and Sebastian Wiederrecht, Odd-Cycle-Packing-treewidth: On the Maximum Independent Set problem in odd-minor-free graph classes, In the Proceedings of ICALP 2026, London, UK, July 7-10), accepted, 2026.

Mamadou Moustapha Kanté gave a talk on characterizing strongly flip-flat graph classes without a large complete bipartite subgraph at the Discrete Math Seminar On April 7, 2026, Mamadou Moustapha Kanté from Université Clermont Auvergne gave a talk at the Discrete Math Seminar on characterizing…

Welcome Marguerite Bin, a new graduate student of the IBS Discrete Mathematics Group The IBS Discrete Mathematics Group welcomes Marguerite Bin, a new graduate student of the Discrete Mathematics Group from April 2, 2026 to May 26, 2026. She is a Ph.D. student at Université de Lorraine. Her…

Tung Nguyen gave a talk on polynomial 𝛘-boundedness of P_5-free graphs at the Discrete Math Seminar On March 31, 2026, Tung Nguyen from the University of Oxford gave a talk at the Discrete Math Seminar on polynomial 𝛘-boundedness of graphs with no induced path on 5 vertices. The title of his talk…

#New_accepted_paper Debsoumya Chakraborti, Minho Cho, *Jinha Kim*, and Minki Kim, Colorful fractional Helly theorem via weak saturation, Electron. J. Combin., accepted, 2026. arxiv.org/abs/2408.15093

4색 정리 새로운 증명이 arXiv에 올라왔습니다. New proof of the four color theorem by Yuta Inoue, Ken-ichi Kawarabayashi, Atsuyuki Miyashita, Bojan Mohar, Carsten Thomassen, Mikkel Thorup arxiv.org/abs/2603.24880

Hidde Koerts gave a talk on characterizing tournaments with no backedge graph of small clique number at the Discrete Math Seminar On March 24, 2026, Hidde Koerts from the University of Waterloo gave a talk at the Discrete Math Seminar on characterizing tournaments with no backedge graph of small…

#New_arXiv_paper Jakob Greilhuber and *Roohani Sharma*, A dividing line for structural kernelization of component order connectivity via distance to bounded pathwidth, 2026. arxiv.org/abs/2603.22240

#New_accepted_paper Seoyoung Kim, Chi Hoi Yip, and *Semin Yoo*, f-Diophantine sets over finite fields via quasi-random hypergraphs from multivariate polynomials, Mathematika, accepted, 2026. arxiv.org/abs/2503.19603

#New_accepted_paper Peter Bradshaw, *Ilkyoo Choi*, Alexandr Kostochka, and Jingwei Xu, A lower bound on the number of edges in DP-critical graphs, J. Combin. Theory Ser. B, accepted, 2026. arxiv.org/abs/2409.00937

József Balogh gave a talk on decomposing (or covering) the edge set of a graph into (or by) cliques at the Discrete Math Seminar On March 12, 2026, József Balogh from the University of Illinois at Urbana-Champaign gave a talk on decomposing the edge set of a graph into edge sets of clliques or…

#New_arXiv_paper *Sang-il Oum* and Marek Sokołowski, Polynomial-size encoding of all cuts of small value in integer-valued symmetric submodular functions, 2026. arxiv.org/abs/2603.10710

Dario Cavallaro gave a talk on well-quasi-ordering of Eulerian digraphs under (strong) immersion at the Discrete Math Seminar On March 10, 2026, Dario Cavallaro from the TU Berlin gave a talk at the Discrete Math Seminar on well-quasi-ordering of Eulerian digraphs under (strong) immersion. The…

As runners move around a track, are they bound to end up “lonely”? Three new proofs suggest the answer is yes — the first significant progress on the problem in decades. www.quantamagazine.org/new-strides-...

Chính T. Hoàng gave a survey talk on graph coloring and forbidden induced subgraphs at the Discrete Math Seminar On March 3, 2026, Chính T. Hoàng from the Wilfrid Laurier University, Waterloo, Canada gave a survey talk on graph coloring and… https://dimag.ibs.re.kr/2026/chinh-t-hoang-seminar/

#New_arXiv_paper Karolina Drabik, Maël Dumas, *Colin Geniet*, Jakub Nowakowski, Michał Pilipczuk, and Szymon Toruńczyk, Variants of Merge-Width and Applications, 2026. arxiv.org/abs/2602.23867

#New_accepted_paper Katie Clinch, Sean Dewar, Niloufar Fuladi, *Maximilian Gorsky*, *Tony Huynh*, Eleftherios Kastis, Atsuhiro Nakamoto, Anthony Nixon, and Brigitte Servatius, Triangulated spheres with holes in triangulated surfaces, Discrete Comput. Geom., accepted, 2026. arxiv.org/abs/2410.04450

#New_arXiv_paper Jorge Olivares-Vinales and *Semin Yoo*, Towers and Bratteli-Vershik systems in Fibonacci-like unimodal maps, 2026. arxiv.org/abs/2602.21623