Bollobás–Riordan polynomial

The Bollobás–Riordan polynomial is a polynomial invariant associated with a graph-like structure called a "graph with a surface". It generalizes several concepts in graph theory, including the Tutte polynomial for planar graphs and other types of polynomials related to graph embeddings. The Bollobás–Riordan polynomial is primarily used in the study of graphs embedded in surfaces, particularly in the context of `k`-edge-connected graphs and their combinatorial properties.