**Mathematics Colloquium (Jointly with ****Knots in Washington XL) **

**Speaker: **Sergei Chmutov, Ohio State University, Mansfield

https://people.math.osu.edu/

**Title: ***In memory of Sergei Duzhin* (1956–2015)

**Abstract**: I will recall life and work of my lifelong friend Sergei Duzhin who suddenly passed away on February 1, 2015. The main topic of my collaboration with Sergei Duzhin was Vassiliev knot invariants. Thus the mathematical part of my talk will concentrate on the theory of these invariants. I will first give definitions, survey the theory, and then explain our results and their further developments. I will then briefly talk about Duzhin’s life and some other of his results.

**Short Bio**: Sergei Chmutovis a professor of Mathematics at Ohio State University, Mansfield. He received his PhD from Moscow State University in 1985. His research interests include Vassiliev theory of knot invariants, knot theory, low-dimensional topology, theory of critical points of functions, combinatorics, (topological) graph theory, theory of singularities of algebraic varieties, and algebraic geometry. He authored 48 research papers and a book (jointly with S. Duzhin and Y. Mostovoy), *Introduction to Vassiliev Knot Invariants,* published by the Cambridge University Press in 2012.