Random Access to Grammar-Compressed Strings and Trees
Grammar-based compression, where one replaces a long string by a small context-free grammar that generates the string, is a simple and powerful paradigm that captures (sometimes with slight reduction in efficiency) many of the popular compression schemes, ...
Testing Probability Distributions using Conditional Samples
We study a new framework for property testing of probability distributions, by considering distribution testing algorithms that have access to a conditional sampling oracle. This is an oracle that takes as input a subset $S \subseteq [N]$ of the domain $[N]$ ...
Low-Distortion Inference of Latent Similarities from a Multiplex Social Network
Much of social network analysis is---implicitly or explicitly---predicated on the assumption that individuals tend to be more similar to their friends than to strangers. Thus, an observed social network provides a noisy signal about the latent underlying “...
Hitting-Sets for ROABP and Sum of Set-Multilinear Circuits
We give an $n^{O(\log n)}$-time ($n$ is the input size) blackbox polynomial identity testing algorithm for unknown-order read-once oblivious arithmetic branching programs (ROABPs). The best time complexity known for blackbox polynomial identity testing (PIT) ...
A Forward-Backward Single-Source Shortest Paths Algorithm
We describe a new forward-backward variant of Dijkstra's and Spira's single-source shortest paths (SSSP) algorithms. While essentially all SSSP algorithms scan edges only forward, the new algorithm scans some edges backward. The new algorithm assumes that ...
Pattern Formation by Oblivious Asynchronous Mobile Robots
We investigate pattern formation, i.e., self-organization, by a swarm of mobile robots, which is closely related with the agreement problem in distributed computing. Consider a system of anonymous mobile robots in a 2-dimensional Euclidean space in which each ...
Regular Graphs and the Spectra of Two-Variable Logic with Counting
The spectrum of a first-order logic sentence is the set of natural numbers that are cardinalities of its finite models. In this paper we show that when restricted to using only two variables, but allowing counting quantifiers, the class of spectra of first-...
Minimum Congestion Mapping in a Cloud
We study a basic resource allocation problem that arises in cloud computing environments. The physical network of the cloud is represented as a graph with vertices representing servers and edges corresponding to communication links. A workload is a set of ...
How to Meet Asynchronously at Polynomial Cost
Two mobile agents starting at different nodes of an unknown network have to meet. This task is known in the literature as rendezvous. Each agent has a different label which is a positive integer known to it but unknown to the other agent. Agents move in an ...
Fast Nonadaptive Deterministic Algorithm for Conflict Resolution in a Dynamic Multiple-Access Channel
A classical problem in addressing a decentralized multiple-access channel is resolving conflicts when a set of stations attempt to transmit at the same time on a shared communication channel. In a static scenario, i.e., when all stations are activated ...