Sciweavers

DM
2008
104views more  DM 2008»
13 years 12 months ago
Improved upper and lower bounds on the feedback vertex numbers of grids and butterflies
We improve upon the best known upper and lower bounds on the sizes of minimal feedback vertex sets in butterflies. Also, we construct new feedback vertex sets in grids so that for...
Florent R. Madelaine, Iain A. Stewart
DCG
2008
88views more  DCG 2008»
13 years 12 months ago
On the Number of Birch Partitions
Birch and Tverberg partitions are closely related concepts from discrete geometry. We show two properties for the number of Birch partitions: Evenness, and a lower bound. This imp...
Stephan Hell
DCG
2008
77views more  DCG 2008»
13 years 12 months ago
Rigidity and the Lower Bound Theorem for Doubly Cohen-Macaulay Complexes
We prove that for d 3, the 1-skeleton of any (d - 1)-dimensional doubly Cohen-Macaulay (abbreviated 2-CM) complex is generically drigid. This implies that Barnette's lower b...
Eran Nevo
DAM
2008
134views more  DAM 2008»
13 years 12 months ago
Efficient algorithms for finding critical subgraphs
This paper presents algorithms to find vertex-critical and edgecritical subgraphs in a given graph G, and demonstrates how these critical subgraphs can be used to determine the ch...
Christian Desrosiers, Philippe Galinier, Alain Her...
ECCC
2010
95views more  ECCC 2010»
13 years 12 months ago
Bounded-depth circuits cannot sample good codes
We study a variant of the classical circuit-lower-bound problems: proving lower bounds for sampling distributions given random bits. We prove a lower bound of 1 - 1/n(1) on the st...
Shachar Lovett, Emanuele Viola
DCC
2010
IEEE
13 years 12 months ago
On multiple caps in finite projective spaces
In this paper, we consider new results on (k, n)-caps with n > 2. We provide a lower bound on the size of such caps. Furthermore, we generalize two product constructions for (k,...
Yves Edel, Ivan N. Landjev
CORR
2008
Springer
115views Education» more  CORR 2008»
13 years 12 months ago
Lower Bounds on the Rate-Distortion Function of LDGM Codes
Abstract-- We analyze the performance of low-density generator matrix (LDGM) codes for lossy source coding. We first develop a generic technique for deriving lower bounds on the ef...
Alexandros G. Dimakis, Martin J. Wainwright, Kanna...
CORR
2008
Springer
86views Education» more  CORR 2008»
13 years 12 months ago
Polygon Exploration with Discrete Vision
With the advent of autonomous robots with two- and three-dimensional scanning capabilities, classical visibility-based exploration methods from computational geometry have gained ...
Sándor P. Fekete, Christiane Schmidt
CORR
2008
Springer
91views Education» more  CORR 2008»
13 years 12 months ago
The Mixing Time of Glauber Dynamics for Colouring Regular Trees
We consider Metropolis Glauber dynamics for sampling proper qcolourings of the n-vertex complete b-ary tree when 3 q b/2 ln(b). We give both upper and lower bounds on the mixing...
Leslie Ann Goldberg, Mark Jerrum, Marek Karpinski
CORR
2008
Springer
138views Education» more  CORR 2008»
13 years 12 months ago
On the Capacity of Free-Space Optical Intensity Channels
New upper and lower bounds are presented on the capacity of the free-space optical intensity channel. This channel is characterized by inputs that are nonnegative (representing the...
Amos Lapidoth, Stefan M. Moser, Michele A. Wigger