Results 1 - 10 of 141,995

Combinatorial Algorithms for Compressed Sensing

by Graham Cormode - In Proc. of SIROCCO , 2006
"... Abstract — In sparse approximation theory, the fundamental problem is to reconstruct a signal A ∈ R n from linear measurements 〈A, ψi 〉 with respect to a dictionary of ψi’s. Recently, there is focus on the novel direction of Compressed Sensing [1] where the reconstruction can be done with very few—O ..."
Abstract - Cited by 116 (1 self) - Add to MetaCart
prior work in other areas including Learning Theory [4], [5], Streaming algorithms [6], [7], [8] and Complexity Theory [9] for this case. Our approach is combinatorial. In particular, we use two parallel sets of group tests, one to filter and the other to certify and estimate; the resulting algorithms

Primal-Dual Combinatorial Algorithms

by Qihui Zhu
"... Linear program and its duality have long been ubiquitous tools for analyzing NP-hard problems and designing fast approximation algorithms. Plotkin et al proposed a primaldual combinatorial algorithm based on linear duality for fractional packing and covering, which achieves significant speedup on a ..."
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Linear program and its duality have long been ubiquitous tools for analyzing NP-hard problems and designing fast approximation algorithms. Plotkin et al proposed a primaldual combinatorial algorithm based on linear duality for fractional packing and covering, which achieves significant speedup on a

Regularity lemmas and combinatorial algorithms

by Nikhil Bansal, Ryan Williams - In Proc. FOCS
"... Abstract — We present new combinatorial algorithms for Boolean matrix multiplication (BMM) and preprocessing a graph to answer independent set queries. We give the first asymptotic improvements on combinatorial algorithms for dense BMM in many years, improving on the “Four Russians ” O(n 3 /(w log n ..."
Abstract - Cited by 19 (3 self) - Add to MetaCart
Abstract — We present new combinatorial algorithms for Boolean matrix multiplication (BMM) and preprocessing a graph to answer independent set queries. We give the first asymptotic improvements on combinatorial algorithms for dense BMM in many years, improving on the “Four Russians ” O(n 3 /(w log

A Combinatorial Algorithm for the Determinant

by Meena Mahajan, V Vinay - In Proceedings of the 8th Annual ACM-SIAM Symposium on Discrete Algorithms , 1997
"... We show the first efficient combinatorial algorithm for the computation of the determinant. Hitherto, all (known) algorithms for determinant have been based on linear algebra. In contrast, our algorithm and its proof of correctness are totally combinatorial in nature. The algorithm requires no divis ..."
Abstract - Cited by 13 (1 self) - Add to MetaCart
We show the first efficient combinatorial algorithm for the computation of the determinant. Hitherto, all (known) algorithms for determinant have been based on linear algebra. In contrast, our algorithm and its proof of correctness are totally combinatorial in nature. The algorithm requires

A Combinatorial Algorithm for Pfaffians

by Meena Mahajan, P.R. Subramanya, V. Vinay , 1999
"... The Pfaffian of a graph is closely linked to Perfect Matching. It is also naturally related to the determinant of an appropriately defined matrix. This relation between Pfaffian and determinant is usually exploited to give a fast algorithm for computing Pfaffians. We present the first completely ..."
Abstract - Cited by 2 (1 self) - Add to MetaCart
completely combinatorial algorithm for computing the Pfaffian in polynomial time. In fact, we show that it can be computed in the complexity class GapL; this result was not known before. Our proof techniques generalize the recent combinatorial characterization of determinant [MV97] in novel ways. As a

Randomised Techniques in Combinatorial Algorithmics

by Michele A. A. Zito , 1999
"... ix Chapter 1 Introduction 1 1.1 Algorithmic Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Technical Preliminaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2.1 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 ..."
Abstract - Cited by 22 (7 self) - Add to MetaCart
ix Chapter 1 Introduction 1 1.1 Algorithmic Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Technical Preliminaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2.1 Problems

A SIMPLE COMBINATORIAL ALGORITHM

by For De, Bruijn Sequences, Abbas Alhakim
"... Abstract. This note presents a combinatorial method to construct a De Bruijn cycle for any order n. 1. ..."
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Abstract. This note presents a combinatorial method to construct a De Bruijn cycle for any order n. 1.

Combinatorial Algorithms for Approximate Words

by Julien Clement, Mathias Vandenbogaert, Milerille Regnier
"... The search and the analysis of motifs on the genome and the proteome is a very active domain in computational biology. The so-called formal approaches search for exceptional words on an entire genome, or some part of it. The specificity of our algorithmic approach is the combination of recent re ..."
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results in probability and combinatorics with highlevel pattern matching algorithms. In this paper, we will concentrate on approximate words. We extend the usual notion of consensus. We provide some combinatorial properties of the approximate words and show how to take advantage of them to assess

Combinatorial Algorithms for the Generalized Circulation Problem

by Andrew V. Goldberg, Serge A. Plotkin, Éva Tardos - MATHEMATICS OF OPERATIONS RESEARCH , 1989
"... We consider a generalization of the maximum flow problem in which the amounts of flow entering and leaving an arc are linearly related. More precisely, if x(e) units of flow enter an arc e, x(e)fl(e) units arrive at the other end. For instance, nodes of the graph can correspond to different curre ..."
Abstract - Cited by 36 (4 self) - Add to MetaCart
. In this paper we present the first polynomial time combinatorial algorithms for this problem. The algorithms are simple and intuitive.

Combinatorics-- Combinatorial algorithm

by Maylis Delest
"... This paper presents a piece of software for the visualization or navigation in trees. It allows some operations as comparison between trees or finding common subtrees. It means a presentation of common things with same colors. Overall implemented tools are strongly based on intrinsic combinatorial p ..."
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This paper presents a piece of software for the visualization or navigation in trees. It allows some operations as comparison between trees or finding common subtrees. It means a presentation of common things with same colors. Overall implemented tools are strongly based on intrinsic combinatorial
Results 1 - 10 of 141,995