Knowledge-Based Synthesis of Distributed Systems Using Event Structures

Abstract

Abstract. To produce a program guaranteed to satisfy a given specification one can synthesize it from a formal constructive proof that a computation satisfying that specification exists. This process is particularly effective if the specifications are written in a high-level language that makes it easy for designers to specify their goals. We consider a high-level specification language that results from adding knowledge to a fragment of Nuprl specifically tailored for specifying distributed protocols, called event theory. We then show how high-level knowledge-based programs can be synthesized from the knowledge-based specifications using a proof development system such as Nuprl. Methods of Halpern and Zuck [20] then apply to convert these knowledge-based protocols to ordinary protocols. These methods can be expressed as heuristic transformation tactics in Nuprl.

A knowledge-based analysis of global function computation

“…Indeed, our hope is that we will be able to synthesize standard programs by starting with high-level kb specifications, synthesizing a kb program that satisfies the specification, and then instantiating the kb program as a standard program. We have some preliminary results along these lines that give us confidence in the general approach [Bickford, Constable, Halpern, and Petride 2005]; we hope that further work will lend further credence to this approach.…”

Velisarios: Byzantine Fault-Tolerant Protocols Powered by Coq

“…every two quorums intersect [59; 83] in sufficiently many replicas. 10 Typically, a quorum corresponds to a majority of nodes that agree on some property. In case of state machine replication, quorums are used to ensure that a majority of nodes agree to update the state using the same operation.…”

“…As Halpern stresses, e.g. in [37], such a definition of knowledge is external in the sense that it cannot necessarily be computed, though some work has been done towards deriving programs from knowledge-based specifications [10]. We follow a different, more pragmatic and computational approach, and say that a node knows some piece of data if it is stored locally, as opposed to the external and logical notion of knowing facts mentioned above.…”