Introductory Workshop - Graph Theory: Extremal, Probabilistic and Structural: Forbidding induced subgraphs: structure and algorithms
Presenter
February 13, 2025
Keywords:
- extremal graph theory
- random graphs
- probabilistic methods
- structural graph theory
- Ramsey theory
MSC:
- 05C35 - Extremal problems in graph theory [See also 90C35]
- 05C55 - Generalized Ramsey theory [See also 05D10]
- 05C75 - Structural characterization of families of graphs
- 05C80 - Random graphs (graph-theoretic aspects) [See also 60B20]
- 05D40 - Probabilistic methods in extremal combinatorics
- including polynomial methods (combinatorial Nullstellensatz
- etc.)
Abstract
Tree decompositions are a powerful tool in both structural graph theory and graph algorithms. Many hard problems become tractable if the input graph is known to have a tree decomposition of bounded “width”. Exhibiting a particular kind of a tree decomposition is also a useful way to describe the structure of a graph. Tree decompositions have traditionally been used in the context of forbidden graph minors; studying them in connection with graph containment relations of more local flavor (such as induced subgraph or induced minors) is a relatively new research direction. In this talk we will discuss recent progress in this area, touching on both the classical notion of bounded tree-width, and concepts of more structural flavor. In particular we will describe a recent result providing a complete list of induced subgraph obstructions to bounded pathwidth.