Seminar - algebraic graph theory

University theorem for polynomial invartiants on ribbon graphs with flags.

Abstract:

In my presentation, I will recall the Bollobas-Riordan polynomial
for ribbon graphs and its universality property. This polynomial finds
an extension on a new category of graphs called ribbon graphs with
flags introduced in arxiv: 1301.1987 [math.CO]. I will discuss the
universality theorem for this new polynomial as well as another
polynomial on some equivalence classes of ribbon graphs generated
by flag moves. My presentation is mainly based on arxiv: 1310.3708 [math.CO].