On February 21, 2023, Meike Hatzel from the National Institute of Informatics in Tokyo gave a talk at the Discrete Math Seminar on the parameterized complexity of the Directed Multicut problem with three pairs of terminals, which is to find a vertex cut of size at most k separating three pairs of terminals. The title of her talk was “Fixed-Parameter Tractability of Directed Multicut with Three Terminal Pairs Parametrised by the Size of the Cutset: Twin-Width Meets Flow-Augmentation“.

## Robert Hickingbotham gave an online talk on the relation between the tree-width and the Hadwiger number of circle graphs at the Virtual Discrete Math Colloquium

On February 15, 2023, Robert Hickingbotham from Monash University gave an online talk at the Virtual Discrete Math Colloquium on the relation between the tree-width and the Hadwiger number of circle graphs. The title of his talk was “Treewidth, Circle Graphs and Circular Drawings“.

## Raphael Steiner gave a talk on a stronger version of Hadwiger’s conjecture at the Discrete Math Seminar

On February 14, 2023, Raphael Steiner from ETH Zürich gave a talk at the Discrete Math Seminar on a stronger version of Hadwiger’s conjecture, which finds a clique minor in which one of its branch set is a singleton. The title of his talk was “Strengthening Hadwiger’s conjecture for 4- and 5-chromatic graphs“. He is currently visiting the IBS discrete mathematics group for 2 weeks.

## Will Perkins gave a lecture for 5 days at the winter school “Statistical Physics and Combinatorics”

On February 6-10, 2023, Will Perkins from Georgia Institute of Technology visited the IBS and gave a lecture for 5 days at the winter school “Statistical Physics and Combinatorics.” This winter school was organized by the IBS Extremal Combinatorics and Probability Group and Shandong University.

## Benjamin Bergougnoux gave an online talk on proving tight lower bounds for the running time of various problems parameterized by rank-width at the Virtual Discrete Math Colloquium

On February 1, 2023, Benjamin Bergougnoux from the University of Warsaw gave an online talk at the Virtual Discrete Math Colloquium about proving tight lower bounds for the running time of various problems parameterized by rank-width. The title of his talk was “Tight Lower Bounds for Problems Parameterized by Rank-width“.

## Abhishek Methuku gave a talk on the resolution of the Erdős-Faber-Lovász conjecture at the Discrete Math Seminar

On January 31, 2023, Abhishek Methuku from ETH Zürich gave a talk at the Discrete Math Seminar on the resolution of the Erdős-Faber-Lovász conjecture for all large instances. The title of his talk was “A proof of the Erdős–Faber–Lovász conjecture“. Abhishek Methuku was a former member of the IBS Discrete Mathematics Group in 2019-2020.