Igor Burban (Mainz)

Title: Vector bundles on cubic curves and Yang-Baxter equations

Abstract: in my talk based on a joint work with Bernd Kreussler I am going to speak about applications of the theory of vector bundles on elliptic curves and their degenerations to the classical and quantum Yang-Baxter equations. This unexpected connection was recently discovered by Polishchuk in a framework of the homological mirror symmetry and his study of A-infinity structures on derived categories of coherent sheaves. By a classical result of Belavin and Drinfeld there are three types of solutions of the classical Yang-Baxter equations: elliptic, trigonometric and rational. It turns out that this trichotomy corresponds exactly to three types of projective curves with trivial canonical bundle: elliptic curves, Kodaira cycles and curves with more complicated singularities like a cuspidal curve. We carry out some explicit calculations of r-matrices and their quantizations coming from singular curves. This approach gives a new insight to a study of degenerations of solutions of the classical and quantum Yang-Baxter equations.