3 papers
math.CO2014
Infinite Gammoids: Minors and Duality
Seyed Hadi Afzali Borujeni, Hiu Fai Law, Malte Müller
This sequel to our paper (Infinite gammoids, 2014) considers minors and duals of infinite gammoids. We prove that a class of gammoids definable by digraphs not containing a certain…
math.CO2013
Infinite strict gammoids
Hadi Afzali, Hiu-Fai Law, Malte Müller
Finite strict gammoids, introduced in the early 1970's, are matroids defined via finite digraphs equipped with some set of sinks: a set of vertices is independent if it admits a li…
math.CO2012
Connected tree-width
Reinhard Diestel, Malte Müller
The connected tree-width of a graph is the minimum width of a tree-decomposition whose parts induce connected subgraphs. Long cycles are examples of graphs that have small tree-wid…