Sciweavers

Share
warning: Creating default object from empty value in /var/www/modules/taxonomy/taxonomy.module on line 1416.
JCT
2008
91views more  JCT 2008»
12 years 12 days ago
A chain theorem for matroids
Tutte's Wheels-and-Whirls Theorem proves that if M is a 3-connected matroid other than a wheel or a whirl, then M has a
James G. Oxley, Charles Semple, Geoff Whittle
JCT
2008
84views more  JCT 2008»
12 years 12 days 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
JCT
2007
94views more  JCT 2007»
12 years 1 months ago
A bijection between 2-triangulations and pairs of non-crossing Dyck paths
A k-triangulation of a convex polygon is a maximal set of diagonals so that no k + 1 of them mutually cross in their interiors. We present a bijection between 2-triangulations of a...
Sergi Elizalde
JCT
2007
142views more  JCT 2007»
12 years 1 months ago
Graphs that triangulate a given surface and quadrangulate another surface
We show that for any closed surface F with χ(F) −4 (or χ(F) −2), there exist graphs that triangulate the torus or the Klein bottle (or the projective plane) and that quadran...
Yusuke Suzuki
JCT
2007
149views more  JCT 2007»
12 years 1 months ago
Weighted forms of Euler's theorem
In answer to a question of Andrews about finding combinatorial proofs of two identities in Ramanujan’s “lost” notebook, we obtain weighted forms of Euler’s theorem on part...
William Y. C. Chen, Kathy Q. Ji
JCT
2006
93views more  JCT 2006»
12 years 1 months ago
Dominating sets in k-majority tournaments
A k-majority tournament T on a finite vertex set V is defined by a set of 2k - 1 linear orderings of V, with u v if and only if u lies above v in at least k of the orders. Motiva...
Noga Alon, Graham Brightwell, Hal A. Kierstead, Al...
JCT
2006
110views more  JCT 2006»
12 years 1 months ago
Branch-width, parse trees, and monadic second-order logic for matroids
Abstract. We introduce "matroid parse trees" which, using only a limited amount of information at each node, can build up the vector representations of matroids of bounde...
Petr Hlinený
JCT
2006
102views more  JCT 2006»
12 years 1 months ago
Hamiltonicity in 3-connected claw-free graphs
Kuipers and Veldman conjectured that any 3-connected claw-free graph with order and minimum degree +6 10 is Hamiltonian for sufficiently large. In this paper, we prove that if...
Hong-Jian Lai, Yehong Shao, Mingquan Zhan
JCT
2006
70views more  JCT 2006»
12 years 1 months ago
Sparse halves in triangle-free graphs
One of Erdos' favourite conjectures was that any triangle-free graph G on n vertices should contain a set of n/2 vertices that spans at most n2/50 edges. We prove this when t...
Peter Keevash, Benny Sudakov
books