Sciweavers

DM
2006
89views more  DM 2006»
14 years 2 days ago
On set systems with a threshold property
For n, k and t such that 1 < t < k < n, a set F of subsets of [n] has the (k, t)threshold property if every k-subset of [n] contains at least t sets from F and every (k -...
Zoltán Füredi, Robert H. Sloan, Ken Ta...
DM
2006
104views more  DM 2006»
14 years 2 days ago
Construction of trees and graphs with equal domination parameters
We provide a simple constructive characterization for trees with equal domination and independent domination numbers, and for trees with equal domination and total domination numb...
Michael Dorfling, Wayne Goddard, Michael A. Hennin...
DM
2006
91views more  DM 2006»
14 years 2 days ago
Restricted Dumont permutations, Dyck paths, and noncrossing partitions
We complete the enumeration of Dumont permutations of the second kind avoiding a pattern of length 4 which is itself a Dumont permutation of the second kind. We also consider some ...
Alexander Burstein, Sergi Elizalde, Toufik Mansour
DM
2006
121views more  DM 2006»
14 years 2 days ago
The acircuitic directed star arboricity of subcubic graphs is at most four
A directed star forest is a forest all of whose components are stars with arcs emanating from the center to the leaves. The acircuitic directed star arboricity of an oriented grap...
Alexandre Pinlou, Eric Sopena
DM
2006
103views more  DM 2006»
14 years 2 days ago
Graph polynomials from principal pivoting
The recursive computation of the interlace polynomial introduced by Arratia, Bollob
Roland Glantz, Marcello Pelillo
DM
2006
89views more  DM 2006»
14 years 2 days ago
On the direct limit of a direct system of multialgebras
We will present some properties of the direct limit of a direct system of multialgebras in a subcategory of the category of multialgebras obtained by considering as morphisms the i...
Cosmin Pelea
DM
2006
86views more  DM 2006»
14 years 2 days ago
Minimal rankings and the arank number of a path
Given a graph G, a function f : V (G) {1, 2, . . . , k} is a k-ranking of G if f (u) = f (v) implies every u - v path contains a vertex w such that f (w) > f (u). A k-ranking ...
Victor Kostyuk, Darren A. Narayan, Victoria A. Wil...
DM
2006
92views more  DM 2006»
14 years 2 days ago
Converse to the Parter-Wiener theorem: The case of non-trees
C. R. Johnson, António Leal Duarte
DM
2006
85views more  DM 2006»
14 years 2 days ago
Transversal numbers of translates of a convex body
Let F be a family of translates of a fixed convex set M in Rn. Let (F) and (F) denote the transversal number and the independence number of F, respectively. We show that (F) (F) 8...
Seog-Jin Kim, Kittikorn Nakprasit, Michael J. Pels...
DM
2006
64views more  DM 2006»
14 years 2 days ago
Path extendability of claw-free graphs
Let G be a connected, locally connected, claw-free graph of order n and x, y be two vertices of G. In this paper, we prove that if for any 2-cut S of G, S {x, y} = , then each (x...
Yu Sheng, Feng Tian, Jianglu Wang, Bing Wei, Yongj...