No abstract

The system decomposes into two parts. The first part allows to prove liveness properties using as axioms theorems of the second part allowing to prove simple safety properties.The completeness proof is constructive and provides a heuristic for proving specific liueness formulas.

No abstract

When considering distributed computing, reliable message-passing synchronous systems on the one side, and asynchronous failure-prone sharedmemory systems on the other side, remain two quite independently studied ends of the reliability/asynchrony spectrum. The concept of locality of a computation is central to the first one, while the concept of wait-freedom is central to the second one. The paper proposes a new DECOU PLED model in an attempt to reconcile these two worlds. It consists of a synchronous and reliable communication graph of n nodes, and on top a set of asynchronous crash-prone processes, each attached to a communication node. To illustrate the DECOU PLED model, the paper presents an asynchronous 3-coloring algorithm for the processes of a ring. From the processes point of view, the algorithm is wait-free. From a locality point of view, each process uses information only from processes at distance O(log * n) from it. This local wait-free algorithm is based on an extension of the classical Cole and Vishkin's vertex coloring algorithm in which the processes are not required to start simultaneously.