ECCC
Electronic Colloquium on Computational Complexity
Login | Register | Classic Style



REPORTS > KEYWORD > SPACE-BOUNDED COMPUTATION:
Reports tagged with space-bounded computation:
TR04-094 | 10th November 2004
Omer Reingold

Undirected ST-Connectivity in Log-Space

We present a deterministic, log-space algorithm that solves st-connectivity in undirected graphs. The previous bound on the space complexity of undirected st-connectivity was log^{4/3}() obtained by Armoni, Ta-Shma, Wigderson and Zhou. As undirected st-connectivity is complete for the class of problems solvable by symmetric, non-deterministic, log-space computations (the class SL), ... more >>>

TR05-022 | 19th February 2005
Omer Reingold, Luca Trevisan, Salil Vadhan

Pseudorandom Walks in Biregular Graphs and the RL vs. L Problem

Motivated by Reingold's recent deterministic log-space algorithm for Undirected S-T Connectivity (ECCC TR 04-94), we revisit the general RL vs. L question, obtaining the following results. 1. We exhibit a new complete problem for RL: S-T Connectivity restricted to directed graphs for which the random walk is promised to have ... more >>>

TR05-092 | 23rd August 2005
Eyal Rozenman, Salil Vadhan

Derandomized Squaring of Graphs

We introduce a "derandomized" analogue of graph squaring. This operation increases the connectivity of the graph (as measured by the second eigenvalue) almost as well as squaring the graph does, yet only increases the degree of the graph by a constant factor, instead of squaring the degree. One application of ... more >>>

TR06-002 | 4th January 2006
Eyal Kaplan, Moni Naor, Omer Reingold

Derandomized Constructions of k-Wise (Almost) Independent Permutations

Constructions of k-wise almost independent permutations have been receiving a growing amount of attention in recent years. However, unlike the case of k-wise independent functions, the size of previously constructed families of such permutations is far from optimal. In this paper we describe a method for reducing the size of ... more >>>

TR07-030 | 29th March 2007
Kai-Min Chung, Omer Reingold, Salil Vadhan

S-T Connectivity on Digraphs with a Known Stationary Distribution

We present a deterministic logspace algorithm for solving s-t connectivity on directed graphs if (i) we are given a stationary distribution for random walk on the graph and (ii) the random walk which starts at the source vertex $s$ has polynomial mixing time. This result generalizes the recent deterministic logspace ... more >>>



ISSN 1433-8092 | Imprint