A new, self-stabilizing algorithm for electing a leader on a unidirectional ring of prime size is presented for the composite atomicity model with a centralized daemon. Its space complexity is optimal to within a small additive constant number of bits per processor, significantly improving previous self-stabilizing algorithms for this problem. In other models or when the ring size is composite, no deterministic solutions exist, because it is impossible to break symmetry.
Faith E. Fich, Colette Johnen