Pathwidth, trees, and random embeddings
arXiv:0910.1409
Abstract
We prove that, for every every shortest-path metric on a graph of pathwidth embeds into a distribution over random trees with distortion at most for some . A well-known conjecture of Gupta, Newman, Rabinovich, and Sinclair states that for every minor-closed family of graphs , there is a constant such that the multi-commodity max-flow/min-cut gap for every flow instance on a graph from is at most . The preceding embedding theorem is used to prove this conjecture whenever the family does not contain all trees.
21 pages