Today, the London Algebra Colloquium began a new year, and a new phase in its history. The Colloquium met at City University for the first time. No institution which was not a college or (in Imperial’s case recently) an ex-college of the University of London has ever been part of the consortium.
I will have to make new headers for the colloquium records!
The history-making talk was a remarkable performance by Robert Marsh, describing his joint work with Jeanne Scott. He first gave us a complete definition of a cluster algebra (no mean feat in itself), then explained carefully how there is a cluster algebra structure on the coordinate ring of a Grassmannian; then we had Postnikov diagrams, illustrated in real time by an example; and finally, the matching polynomial of a weighted bipartite graph sitting in the Postnikov diagram turned out to be a renormalised version of the function expressing a “twisted” Plücker coordinate in terms of the cluster variables. Phew!
If you want to know more, you should have been at the talk …