## Hong Liu gave a talk on the conjecture of Mader about the topological minors in C4-free graphs at the discrete math seminar

On December 12, 2019, Hong Liu from University of Warwick gave a talk on the resolution of the conjecture of Mader on the existence of a complete topological minor under the condition of average degree for C4-free graphs at the discrete math seminar held at KAIST. The title of his talk was “A proof of Mader’s conjecture on large clique subdivisions in $C_4$-free graphs“.

## Ruth Luo gave a talk on the induced Turán-type problems for hypergraphs at the discrete math seminar

On November 19, 2019, Ruth Luo from University of California San Diego gave a talk on the Turán-type results on r-uniform hypergraphs without a certain structure called an induced Berge-F. The title of her talk was “Induced Turán problems for hypergraphs“. She is visiting IBS discrete mathematics group until November 22.

## Pascal Gollin gave a talk on the existence of a decomposition of an infinite graph into spanning trees at the discrete math seminar

On October 29, 2019, Pascal Gollin from IBS discrete mathematics group gave a talk on the existence of a decomposition of an infinite graph into spanning trees in terms of the existence of packing and covering of spanning trees at the discrete math seminar. The title of his talk was “A Cantor-Bernstein-type theorem for spanning trees in infinite graphs“.

## Zi-Xia Song (宋梓霞) gave a talk on Ramsey numbers under Gallai colorings at the discrete math seminar

On October 15, 2019, Prof Zi-Xia Song (宋梓霞) from University of Central Florida (UCF) presented a talk about Ramsey numbers under Gallai colorings. The title of her talk was “Ramsey numbers of cycles under Gallai colorings.”

## Alexandr V. Kostochka gave a colloquium talk on Ramsey-type problems for paths and cycles at the KAIST MathSci – IBS DIMAG Joint Colloquium

On October 8, 2019, Prof. Alexandr V. Kostochka from the University of Illinois at Urbana-Champaign gave a colloquium talk at the KAIST Mathematical Sciences – IBS Discrete Mathematics Group Joint Colloquium. The title of his talk was “On Ramsey-type problems for paths and cycles in dense graphs“. He will stay one week at IBS Discrete Mathematics Group.