Heterogeneous active agents, III: Polynomially implementable agents

In [17], two of the authors have introduced techniques to build agents on top of arbitrary data structures, and to “agentize” new/existing programs. They provided a series of successively more sophisticated semantics for such agent systems, and showed that as these semantics become epistemically more desirable, a computational price may need to be paid. In this paper, we identify a class of agents that are called weakly regular—this is done by first identifying a fragment of agent programs [17] called weakly regular agent programs (WRAPs for short). It is shown that WRAPs are definable via three parameters—checking for a property called “safety”, checking for a property called “conflict freedom” and checking for a “deontic stratifiability” property. Algorithms for each of these are developed. A weakly regular agent is then defined in terms of these concepts , and a regular agent is one that satisfies an additional boundedness property. We then describe a polynomial algorithm that computes (under suitable assumptions) the reasonable status set semantics of regular agents—this semantics was identified in [17] as being epistemically most desirable. Though this semantics is coNP-complete for arbitrary agent programs [16], it is polynomially computable via our algorithm for regular agents. Finally, we describe our implementation architecture and provide details of how we have implemented RAPs, together with experimental results.