On August 17, 2021, Linda Cook from the IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on (1) a polynomial-time algorithm to detect long even holes and (2) a structure of graphs with no holes of length≠𝓁 for a fixed 𝓁≥7. The title of her talk was “Two results on graphs with holes of restricted lengths“.

## Welcome Linda Cook, a new member of IBS Discrete Mathematics Group

The IBS discrete mathematics group welcomes Dr. **Linda Cook**, a new research fellow at the IBS discrete mathematics group from August 1, 2021. She received her Ph.D. from the Program in Applied and Computational Mathematics at Princeton University under the supervision of Prof. Paul Seymour. She is interested in structural graph theory and its algorithmic applications.

## Duksang Lee (이덕상) gave a talk on intertwining connectivities for vertex-minors and pivot-minors of graphs at the Discrete Math Seminar

On August 10, 2021, Duksang Lee (이덕상) from KAIST and IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar, showing that there are finitely many pivot-minor-minimal graphs preserving the rank connectivity between two fixed pairs of vertex sets. The title of his talk was “Intertwining connectivities for vertex-minors and pivot-minors“.

## Pascal Gollin has been appointed as the Young Scientist Fellow (YSF) of IBS

Pascal Gollin from the IBS Discrete Mathematics Group has been appointed as the IBS Young Scientist Fellow as of August 1, 2021. The title of his research proposal was “*Structural questions for infinite graphs, digraphs, and matroids*“. Congratulations!

## Maria Chudnovsky gave an online talk on structural aspects of tree-width of graphs in terms of induced subgraphs at the Virtual Discrete Math Colloquium

On July 28, 2021, Maria Chudnovsky from Princeton University gave an online talk at the Virtual Discrete Math Colloquium on structural aspects of graphs of large tree-width in terms of induced subgraphs. The title of her talk was “Induced subgraphs and tree decompositions“.

## Euiwoong Lee (이의웅) gave a talk on the minimum k-cut problem at the Discrete Math Seminar

On July 27, 2021, Euiwoong Lee (이의웅) from the University of Michigan gave a talk at the Discrete Math Seminar on the proof that the Karger-Stein algorithm finds the minimum k-cuts with the probability $\Omega(n^{-k})$, which is tight and improves previous bounds. The title of his talk was “The Karger-Stein algorithm is optimal for k-cut“.

## Semin Yoo (유세민) gave a talk on an analogue of q-binomial coefficients at the Discrete Math Seminar

On July 20, 2021, Semin Yoo (유세민) from the University of Rochester gave a talk on an analogue of q-binomial coefficients, counting subspaces having the Euclidean quadratic form, and its applications at the Discrete Math Seminar. She will move to KIAS next month as a postdoc. The title of her talk was “Combinatorics of Euclidean spaces over finite fields“.

## Stefan Weltge gave an online talk at the Virtual Discrete Math Colloquium on a strongly polynomial-time algorithm for the integer linear program with bounded subdeterminants and two nonzeros per row

On July 14, 2021, Stefan Weltge from the Technical University of Munich gave an online talk at the Virtual Discrete Math Colloquium on an efficient algorithm to solve the Integer Linear Program defined by an integer matrix whose subdeterminants are bounded by a constant and that contains at most two nonzero entries in each row. The title of his talk was “Integer programs with bounded subdeterminants and two nonzeros per row“.

## Jaehoon Kim (김재훈) gave a talk on the minimum spectral radius of $K_{r+1}$-saturated graphs at the Discrete Math Seminar

On July 13, 2021, Jaehoon Kim (김재훈) from KAIST gave a talk at the Discrete Math Seminar on a lower bound on the spectral radius of a $K_{r+1}$-saturated graph. The title of his talk was “$K_{r+1}$-saturated graphs with small spectral radius“.

## Suil O (오수일) gave a talk on the existence of even and odd [a,b]-factors in h-edge-connected r-regular graphs in terms of eigenvalues at the Discrete Math Seminar

On July 6, 2021, Suil O (오수일) from SUNY Korea gave a talk at the Discrete Math Seminar on upper bounds of certain eigenvalues to guarantee the existence of an even or odd [a,b]-factor in h-edge-connected r-regular graphs. The title of his talk was “Eigenvalues and [a, b]-factors in regular graphs“.