One of the greatest discovery of in the theory of distance-regular graphs has been the twisted Grassmann graph by Edwin van Dam and Jack Koolen. Here I want to describe a small variation of their construction for the twisted $ {D_{5,5}(q)}$ graph. This post mostly to preserve my blackboard on the topic. (I tend to […]
I have uploaded a preprint which concludes a joint work with John Bamberg and Ferdinand Ihringer that started last year during their visit to TU Delft. In this work, we have done one of my favorite things in mathematics research: combining unrelated topics to create something new in each of them. Here is a quick […]
A few days ago China celebrated one of many Chinese Valentine’s days: the 20th of May. Why is this a special day in China? Chinese has around 30 to 36 phonemes which is plenty, but Chinese phonotactics dictate that you can only make around 1200 syllables out of them, for instance, see this video. English […]
Last year Zhirayr Avetisyan and I created a math riddle about the games cops and robbers. It was part of an outreach event to high-school student at Ghent University. You can find it in this post here. The story was that a group of mathematicians wants to walk around the city of Ghent and have […]
The work of mathematicians goes through peer-review which contributes to the acceptance of the correctness of our work. Peer-reviewers are of course peers, that is other mathematicians, and most of us consider this work important. At least two of my colleagues complain about how much they have to referee and (they claim) give my name […]
This week I put two new preprint on the arXiv. Both are on a similar theme, so I will discuss them together. One is with Morgan Rodgers on regular sets of lines in rank 3 polar spaces. The other one is solves a problem which I have been thinking about very regularly since November 2017: […]
This is not a proper “I have jobs! Please apply!” post, but more a general service announcement. It is my understanding that I can essentially have up to two post-docs here at the Southern University of Science and Technology (SUSTech) in Shenzhen without having to worry about funding too much. Shenzhen is one of the […]
Apparently, I described a very elegant argument to give a lower bound on the second largest eigenvalue of the adjacency matrix of a regular graph last year. This was pointed out in two recent preprints by Eero Räty, Benny Sudakov, and Istvan Tomon. This blog post is to describe the very short argument and how […]
Let me start with a small service announcement. In November I am taking up a position as an tenure-track assistant at the Southern University of Science and Technology in Shenzhen. At least if everything goes well. Airplanes can crash or I could fail the medical examination. The date of my flight is easy to remember. […]