Randomized Priority Algorithms: (Extended Abstract)

Spyros Angelopoulos

Abstract: In a paper of Borodin, Nielsen and Rackoff [8], a framework for abstracting the properties of deterministic greedy-like algorithms was proposed. We extend their model so as to formally define ”randomized greedy-like algorithms” and be able to prove lower bounds on the approximability of a certain problem by such a class of algorithms. We show how our techniques can be applied in well-studied problems such as the facility location and makespan scheduling problems, for which both upper and lower bounds on the approximation ratio achieved by deterministic greedy-like algorithms are known.