Archive for May, 2010

First Montreal Spring School in Graph Theory

May 13, 2010

I am attending this one-month summer school in Structural Graph Theory, which is held in Montreal. It is a high-level school with world-class speakers, and I am really enjoying it. We have two classes everyday for four weeks, making a total of 40 lectues.

Paul Seymour talks about excluding induced subgraphs, and, in particular, will sketch a proof of the Strong Perfect Graph Theorem, which he (together with Chudnovsky, Robertson and Thomas) has proved in 2001. This was a huge result, with a 150-pages proof. Not only is he a great problem-solver, but also he is a great teacher. I really do enjoy sitting in his class. He is so smart, draws lots of pictures, and always proves what he wants in a bottom-up way; That is, unlike many others who first write a Theorem statement formally and then write the proof, he first describes intuitively why such a Theorem has to be true, and only then writes it down.

Maria Chudnovsky (the picture is a bit old) also talks about excluding induced subgraphs, but her lectures are independent of the Paul’s. She is also smart and a good instructor (she was Paul’s PhD student and must have learnt a lot from him).

Bruce Reed talks about excluding minors from graphs. In particular he talks about Robertson and Seymour’s Graphs Minor Project. He is a great researcher. Sometimes his lectures are confusing for me, in particular when he talks about planar graphs. Fortunately he has now turned to tree decompositions, which I am a little familiar with.

To summarize, I am so glad that I am attending this school. Structural Graph Theory is really nice (though hard to prove new results) and I enjoy sitting in the classes and working on the assignments. It is like I am back in the IMO training camp (7 years ago)! The city of Montreal is also very nice. Here you see a photo I took in the botanical garden, which I went to see on May 8th.