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Quasi-PTAS for Scheduling with Precedences using LP Hierarchies

2017/08/15 by Garg, Shashwat · 1 citation
#Data Structures and Algorithms (cs.DS) #FOS: Computer and information sciences

paper · doi:10.48550/arxiv.1708.04369

Abstract

A central problem in scheduling is to schedule n unit size jobs with precedence constraints on m identical machines so as to minimize the makespan. For m=3, it is not even known if the problem is NP-hard and this is one of the last open problems from the book of Garey and Johnson. We show that for fixed m and ε, (log n)O(1) rounds of Sherali-Adams hierarchy applied to a natural LP of the problem provides a (1+ε)-approximation algorithm running in quasi-polynomial time. This improves over the recent result of Levey and Rothvoss, who used r=(log n)O(log log n) rounds of Sherali-Adams in order to get a (1+ε)-approximation algorithm with a running time of nO(r).

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