**Title:**A new method to distinguish Legendrian knots

**Speaker:** Ivan Dynnikov, Steklov Mathematical Institute, Moscow

**Abstract: **The talk is based on a joint ongoing work with Maxim Prasolov. Our main objects of interest are rectangular diagrams of knots, which are a promising tool in knot theory. They appear to be intimately related to Legendrian knots. Whereas the problem of comparing topological types of two knots is solvable both theoretically and---for a small number of crossings---practically, there is no regular method to decide whether two Legendrian knots having the same topological type and the same classical invariants are equivalent or not. A lot is known in particular cases, but there remain open questions already for knots with just six crossings.

Recently we extended the formalism of rectangular diagrams to representation of surfaces. This formalism turned out to work nicely for Giroux' convex surfaces. The latter are very useful for distinguishing contact structures and Legendrian knots. By using our formalism and properties of Giroux's convex surfaces we introduced a combinatorial method to distinguish Legendrian knots, which I will overview after introducing the basic notions of the subject like rectangular diagram or Legendrian knot.

**Short bio:**After obtaining his PhD from Moscow State University in 1996, Ivan Dynnikov has had teaching positions in MSU where he is a professor since 2007. Since 2009, he works as a researcher in Steklov Mathematical Institute. Dynnikov was awarded Moscow Mathematical Society Prize in 2000. He specializes in low dimensional topology, dynamical systems, and mathematical physics.