 
Summary: A Theory of Competitive Analysis for Distributed Algorithms
Miklos Ajtai
James Aspnes
Cynthia Dwork
Orli Waarts§
June 10, 2003
Abstract
We introduce a theory of competitive analysis for distributed algorithms. The first steps
in this direction were made in the seminal papers of Bartal, Fiat, and Rabani [18], and of
Awerbuch, Kutten, and Peleg [16], in the context of data management and job scheduling.
In these papers, as well as in other subsequent work [4, 15, 19, 14], the cost of a distributed
algorithm is compared to the cost of an optimal globalcontrol algorithm. (This is also done
implicitly in the earlier work of Awerbuch and Peleg [17].) Here we introduce a more refined
notion of competitiveness for distributed algorithms, one that reflects the performance of
distributed algorithms more accurately. In particular, our theory allows one to compare
the cost of a distributed online algorithm to the cost of an optimal distributed algorithm.
We demonstrate our method by studying the cooperative collect primitive, first ab
stracted by Saks, Shavit, and Woll [57]. We present two algorithms (with different strengths)
for this primitive, and provide a competitive analysis for each one.
