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ESA
2011
Springer
260views Algorithms» more  ESA 2011»
12 years 10 months ago
On Variants of the Matroid Secretary Problem
We present a number of positive and negative results for variants of the matroid secretary problem. Most notably, we design a constant-factor competitive algorithm for the “rando...
Shayan Oveis Gharan, Jan Vondrák
JCT
2010
79views more  JCT 2010»
13 years 5 months ago
Confinement of matroid representations to subsets of partial fields
Let M be a matroid representable over a (partial) field and B a matrix representable over a sub-partial field . We say that B confines M to if, whenever a -representation matrix ...
Rudi Pendavingh, Stefan H. M. van Zwam
JCT
2010
85views more  JCT 2010»
13 years 9 months ago
On inequivalent representations of matroids over non-prime fields
Abstract. For each finite field F of prime order there is a constant c such that every 4-connected matroid has at most c inequivalent representations over F. We had hoped that th...
Jim Geelen, Bert Gerards, Geoff Whittle
JCT
2010
61views more  JCT 2010»
13 years 9 months ago
The projective plane is a stabilizer
We prove that every 3-connected GF(q)-representable matroid that contains the projective plane, PG(2, q), as a minor is uniquely representable.
Jim Geelen, Geoff Whittle
JCT
2008
84views more  JCT 2008»
13 years 9 months ago
Wild triangles in 3-connected matroids
Let {a, b, c} be a triangle in a 3-connected matroid M. In this paper, we describe the structure of M relative to {a, b, c} when, for all t in {a, b, c}, either M\t is not 3-connec...
James G. Oxley, Charles Semple, Geoff Whittle
DM
1998
195views more  DM 1998»
13 years 10 months ago
On basis-exchange properties for matroids
We give a counterexample to a conjecture by Wild about binary matroids. We connect two equivalent lines of research in matroid theory: a simple type of basis-exchange property and ...
Joseph E. Bonin
COMBINATORICS
1998
84views more  COMBINATORICS 1998»
13 years 10 months ago
Multimatroids II. Orthogonality, minors and connectivity
A multimatroid is a combinatorial structure that encompasses matroids, delta-matroids and isotropic systems. This structure has been introduced to unify a theorem of Edmonds on th...
André Bouchet
ENTCS
2002
93views more  ENTCS 2002»
13 years 10 months ago
Matroids from modules
The aim of this work is to show that (oriented) matroid methods can be applied to many discrete geometries, namely those based on modules over integral (ordered) domains. The tric...
Nils Anders Danielsson, Michael B. Smyth
EJC
2002
13 years 10 months ago
Cycle Cover Ratio of Regular Matroids
A cycle in a matroid is a disjoint union of circuits. This paper proves that every regular matroid M without coloops has a set S of cycles whose union is E(M) such that every elem...
Hong-Jian Lai, Hoifung Poon
EJC
2002
13 years 10 months ago
Bases in Orlik-Solomon Type Algebras
The Orlik-Solomon algebra of a matroid M is the quotient of the exterior algebra on the points by the ideal (M) generated by the boundaries of the circuits of the matroid. There i...
David Forge