Title
Structural properties of greedoids
Abstract
Greedoids were introduced by the authors as generalizations of matroids providing a framework for the greedy algorithm. In this paper they are studied from a structural aspect. Definitions of basic matroid-theoretical concepts such as rank and closure can be generalized to greedoids, even though they loose some of their fundamental properties. The rank function of a greedoid is only “locally” submodular. The closure operator is not monotone but possesses a (relaxed) Steinitz—McLane exchange property. We define two classes of subsets, called rank-feasible and closure-feasible, so that the rank and closure behave nicely for them. In particular, restricted to rank-feasible sets the rank function is submodular. Finally we show that Rado’s theorem on independent transversals of subsets of matroids remains valid for feasible transversals of certain sets of greedoids.
Year
DOI
Venue
1983
10.1007/BF02579192
Combinatorica
Keywords
Field
DocType
greedy algorithm,closure operator
Matroid,Discrete mathematics,Combinatorics,Closure operator,Generalization,Submodular set function,Greedy algorithm,Transversal (geometry),Greedoid,Mathematics,Monotone polygon
Journal
Volume
Issue
ISSN
3
3
1439-6912
Citations 
PageRank 
References 
16
5.40
2
Authors
2
Name
Order
Citations
PageRank
Bernhard Korte1175.90
László Lovász22640881.45