On September 19, 2023, Donggyu Kim (김동규) from KAIST and the IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on defining orthogonal matroids (or, equivalently even delta-matroids) over tracts and its applications to several theorems regarding representability. The title of his talk was “Orthogonal matroids over tracts.”

## We are hiring: The IBS Discrete Mathematics Group (DIMAG) Research Fellowship (Due: Dec. 3, 2023)

The IBS Discrete Mathematics Group (DIMAG, https://dimag.ibs.re.kr/) in Daejeon, Korea invites applications for three research fellowship positions.

DIMAG is a research group that was established on December 1, 2018 at the Institute for Basic Science (IBS), led by Prof. Sang-il Oum. DIMAG is located at the headquarters of the Institute for Basic Science (IBS) in Daejeon, South Korea, a city of 1.5 million people.

Currently, DIMAG consists of researchers from various countries such as Korea, the USA, Germany, Canada, and Australia, and the work is done in English. DIMAG is co-located with the IBS Extremal Combinatorics and Probability Group (ECOPRO).

Successful candidates for research fellowship positions will be new or recent Ph.D.’s with outstanding research potential in all fields of **discrete mathematics** with emphasis on **structural graph theory**, **combinatorial optimization**, **matroid theory**, and **algorithms**.

These appointments are for about two years, and the starting salary is no less than KRW 59,000,000. The appointment is one-time renewable **up to 5 years in total** contingent upon the outstanding performance of the researcher. The expected appointment date is September 1, 2024, but it is negotiable within the same calendar year.

These are purely research positions and will have no teaching duties.

A complete application packet should include:

- AMS standard cover sheet (preferred) or cover letter (PDF format)
- Curriculum vitae including a publication list (PDF format)
- Research statement (PDF format)
- Application for the IBS & Consent to Collection and Use of Personal Information (PDF file)
- At least 3 recommendation letters

For full consideration, applicants should email items 1, 2, 3, and 4 and arrange their recommendation letters emailed to dimag@ibs.re.kr by December 3, 2023, Sunday. (Anywhere on Earth)

Recommendation letters forwarded by an applicant will not be considered.

DIMAG encourages applications from individuals of diverse backgrounds.

*For Korean citizens who have not yet completed their military duty: *전문연구요원 종사를 희망하는 경우에는 지원 의사와 병역 관계를 cover letter 및 이메일 등에 표시하여 제출 필요. 다만 현역입영대상자의 전문연구요원 신규 편입은 불가하며, 보충역 대상자 및 타 기관에서 전직해서 오는 경우에 한하여 지원 가능(반드시 타 기관에서 전직 요건이 충족되는 등 전직 요건이 충족 되어야만 함)

## Seog-Jin Kim (김석진) gave a talk on the list chromatic number of the square of subcubic planar graphs of girth at least 6 at the Discrete Math Seminar

On September 12, 2023, Seog-Jin Kim (김석진) from Konkuk University gave a talk at the Discrete Math Seminar on the list chromatic number of the square of subcubic planar graphs of girth at least 6. The title of his talk was “The square of every subcubic planar graph of girth at least 6 is 7-choosable“.

## Welcome Yuzhen Qi from Shandong University, a new visiting graduate student at the IBS Extremal Combinatorics and Probability Group

The IBS Discrete Mathematics Group welcomes Yuzhen Qi, a new visiting student of the IBS Extremal Combinatorics and Probability Group. She is currently a graduate student of Shandong University. She arrived at IBS on September 7, 2023 and will stay with us until September 7, 2025.

## Sebastian Wiederrecht gave a talk on the Erdős-Pósa property of H-minors in a graph from a minor-closed class of graphs for Kuratowski-connected shallow-vortex minors H at the Discrete Math Seminar

On September 5, 2023, Sebastian Wiederrecht from the IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on the Erdős-Pósa property of H-minors in a graph from a minor-closed class of graphs for Kuratowski-connected shallow-vortex minors H. The title of his talk was “Delineating half-integrality of the Erdős-Pósa property for minors“.

## Welcome Bingyu Luan from Shandong University and Shuaichao Wang from Nankai University, new visiting graduate students in the IBS Extremal Combinatorics and Probability Group

The IBS Discrete Mathematics Group welcomes Bingyu Luan and Shuaichao Wang, new visiting students of the IBS Extremal Combinatorics and Probability Group.

Bingyu Luan is currently a graduate student of Shandong University. She arrived at IBS on August 31, 2023 and will stay with us until August 31, 2025.

Shuaichao Wang is currently a graduate student of Nankai University. He arrived at IBS on August 31, 2023 and will stay with us until August 31, 2025.

## Dabeen Lee (이다빈) gave a talk on characterizing ideal multipartite clutters constructed from subspaces of finite vector spaces in terms of forbidden clutter minors at the Discrete Math Seminar

On August 29, 2023, Dabeen Lee (이다빈) from KAIST gave a talk at the Discrete Math Seminar on characterizing ideal multipartite clutters constructed from subspaces of finite vector spaces in terms of forbidden clutter minors. The title of his talk was “From coordinate subspaces over finite fields to ideal multipartite uniform clutters.”

## Linda Cook gave a talk on bounding the dichromatic number after forbidding a fixed orientation of a path at the Discrete Math Seminar

On August 22, 2023, Linda Cook from the IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on bounding the dichromatic number of a directed graph not having an induced subgraph isomorphic to a fixed orientation of a path. The title of her talk was “Orientations of P_4 bind the dichromatic number”.

## R. Amzi Jeffs gave a talk on the intersection patterns of convex sets at the Discrete Math Seminar

On August 9, 2023, R. Amzi Jeffs from Carnegie Mellon University gave a talk at the Discrete Math Seminar on the simplicial complexes and convex codes arising from the intersections of convex sets. The title of his talk was “Intersection patterns of convex sets“.

## The 2023 Mini-Workshop on Discrete Geometry was held on August 9 with three talks by Michael Dobbins, Andreas Holmsen, and Minki Kim

On August 9, 2023, the 2023 Mini-Workshop on Discrete Geometry was held at the IBS. This workshop consisted of three talks by Michael Dobbins from SUNY Binghamton, Andreas Holmsen from KAIST, and Minki Kim from GIST. Here is the list of talks.

- Michael Dobbins (SUNY Binghamton):
*Colorful intersections, Tverberg partitions, and geometric transversals* - Andreas Holmsen (KAIST):
*The topology of the complex of ordered partitions* - Minki Kim
^{김민기}(GIST):*Some variants of the colorful Helly theorems*