Search

Summary

An abstract simplicial complex C is said to be k-connected if for each $-1\leq d\leq k$ and each continuous map f from the sphere $S^d$ to ||C|| (the body of the geometric realization of C), the map f can be extended to a continuous map from the ball $B^{d+1}$ to ||C||. In 2000 a link was discovered between the topological connectedness of the independence complex of a graph and various other important graph parameters to do with colouring and partitioning. When the graph represents some other combinatorial structure, for example when it is the line graph of a hypergraph H, this link can be exploited to obtain information such as lower bounds on the matching number of H. Since its discovery there have been many other applications of this phenomenon to combinatorial problems. The aim of this article is to outline this general method and to describe some of its applications.

We prove that the potential extreme Khovanov cohomology of a link is the cohomology of the independence simplicial complex of its Lando graph. We also provide a family of knots having as many non-trivial extreme Khovanov cohomology modules as desired, that is, examples of H-thick knots that are as far from being H-thin as desired.

Search Results

Refine search

Refine search

Actions for selected content:

2 results

3 - Topological connectedness and independent sets in graphs

Summary

A geometric description of the extreme Khovanov cohomology

Search Results

Refine search

Refine search

Actions for selected content:

Save Search

2 results

3 - Topological connectedness and independent sets in graphs

Summary

A geometric description of the extreme Khovanov cohomology