The connectivity of the basis graph of a branching greedoid

Abstract

A result of Korte and Lovász states that the basis graph of every 2- connected greedoid is connected. We prove that the basis graph of every 3-connected branching greedoid is ( -- 1)-connected, where is the minimum in-degree (disregarding the root) of the underlying rooted directed (multi) graph. We also give examples showing that this results is (in some sense) best possible