40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) (1999)
New York, New York
Oct. 17, 1999 to Oct. 18, 1999
Elias Koutsoupias , University of California at Los Angeles
We study the k-server problem when the off-line algorithm has fewer than k servers. We give two upper bounds of the cost WFA(\math) of the Work Function Algorithm. The first upper bound is \math, where \math denotes the optimal cost to service \math by m servers. The second upper bound is \math for \math. Both bounds imply that the Work Function Algorithm is (2k-1)-competitive. Perhaps more important is our technique which seems promising for settling the k-server conjecture. The proofs are simple and intuitive and they do not involve potential functions. We also apply the technique to give a simple condition for the Work Function Algorithm to be k-competitive; this condition results in a new proof that the k-server conjecture holds for k=2.
E. Koutsoupias, "Weak Adversaries for the k-Server Problem," 40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039)(FOCS), New York, New York, 1999, pp. 444.