Title
Expressiveness of communication in answer set programming.
Abstract
Answer set programming (ASP) is a form of declarative programming that allows to succinctly formulate and efficiently solve complex problems. An intuitive extension of this formalism is communicating ASP, in which multiple ASP programs collaborate to solve the problem at hand. However, the expressiveness of communicating ASP has not been thoroughly studied. In this paper, we present a systematic study of the additional expressiveness offered by allowing ASP programs to communicate. First, we consider a simple form of communication where programs are only allowed to ask questions to each other. For the most part, we deliberately consider only simple programs, i.e. programs for which computing the answer sets is in P. We find that the problem of deciding whether a literal is in some answer set of a communicating ASP program using simple communication is NP-hard. In other words, due to the ability of these simple ASP programs to communicate and collaborate, we move up a step in the polynomial hierarchy. Second, we modify the communication mechanism to also allow us to focus on a sequence of communicating programs, where each program in the sequence may successively remove some of the remaining models. This mimics a network of leaders, where the first leader has the first say and may remove models that he or she finds unsatisfactory. Using this particular communication mechanism allows us to capture the entire polynomial hierarchy. This means, in particular, that communicating ASP could be used to solve problems that are above the second level of polynomial hierarchy, such as some forms of abductive reasoning as well as PSPACE-complete problems such as STRIPS planning.
Year
DOI
Venue
2011
10.1017/S1471068411000561
THEORY AND PRACTICE OF LOGIC PROGRAMMING
Keywords
DocType
Volume
logic programming,answer set programming,multi-agent reasoning
Journal
13
Issue
ISSN
Citations 
3
1471-0684
1
PageRank 
References 
Authors
0.34
27
5
Name
Order
Citations
PageRank
Kim Bauters1387.91
Steven Schockaert258357.95
Jeroen Janssen3716.17
Dirk Vermeir469485.34
Martine De Cock5134196.06