Proceedings 41st Annual Symposium on Foundations of Computer Science (2000)
Redondo Beach, California
Nov. 12, 2000 to Nov. 14, 2000
M. Herlihy , Dept. of Comput. Sci., Brown Univ., Providence, RI, USA
E. Ruppert , Dept. of Comput. Sci., Brown Univ., Providence, RI, USA
A data type's consensus number measures its power in asynchronous concurrent models of computation. We characterize the circumstances under which types of high consensus number can be constructed from types with lower consensus numbers, a process called boosting. In settings where boosting is impossible, we can reason about the synchronization power of objects in isolation. We give a new and simple topological condition, called /spl kappa/-solo-connectivity sufficient to ensure that one-shot types cannot be boosted to consensus number /spl kappa/. The booster type need not be one-shot; it can be arbitrary. We also show that, for /spl kappa/<2, any type that is not /spl kappa/-solo-connected can be boosted to consensus number /spl kappa/. For types that can be boosted, we establish an upper bound on the amount the consensus number can be increased. For finite types, these properties and bounds are computable. For deterministic one-shot types, the /spl kappa/-solo-connectivity property also exactly characterizes the types that have consensus number less than /spl kappa/.
distributed algorithms; concurrency theory; type theory; synchronisation; booster types; data type; consensus number; asynchronous concurrent models of computation; synchronization power; topological condition; solo-connectivity; upper bound; deterministic one-shot types
E. Ruppert and M. Herlihy, "On the existence of booster types," Proceedings 41st Annual Symposium on Foundations of Computer Science(FOCS), Redondo Beach, California, 2000, pp. 653.