Modularity is essential for modeling large-scale practical applications. We propose modular logic programs as a modular version of answer set programming and study the relationship of our formalism to an earlier concept

We present new complexity results on answer set checking for nonground programs under a variety of syntactic restrictions. For several of these problems, the kind of representation of the answer set to be checked is important. In particular, we consider set-based and bitmap-based representations, which are popular in implementations of Answer Set Programming systems. Furthermore, we present new...

We present a new approach to integrating Constraint Processing (CP) techniques into Answer Set Programming (ASP). Based on an alternative semantic approach, we develop an algorithmic framework for conflict-driven ASP solving that exploits CP solving capacities. A significant technical issue concerns the combination of conflict information from different solver types. We have implemented our app...

Several proposals of the semantics of aggregates are based on different extensions of the stable model semantics, which makes it difficult to compare them. In this note, building upon a reductive approach to designing aggregates, we provide reformulations of some existing semantics in terms of propositional formulas, which help us compare the semantics and understand their properties in terms o...

The aggregates have greatly extended the representation power, in both theory and practice, of Answer Set Programming. Significant understanding of programs with aggregates has been gained in the last decade. However, there is still a substantial difficulty in understanding the semantics due to the nonmonotonic behavior of aggregates, which is demonstrated by several distinct semantics for aggr...

This paper presents a compilation scheme, called ASP2AR, for translating ASP into event-driven action rules. For an ASP program, the generated program maintains a partial answer set as a pair of sets of tuples (called IN and OUT ) and propagates updates to these sets using action rules. To facilitate propagation, we encode each set as a finite-domain variable and treat additions of tuples into ...

A number of different Fuzzy Answer Set Programming (FASP) formalisms have been proposed in the last years, which all differ in the language extensions they support. In this paper we investigate the expressivity of these frameworks. Specifically we show how a variety of constructs in these languages can be implemented using a considerably simpler core language. These simulations are important as...

In this paper, we propose a progression semantics for firstorder answer set programs. Based on this new semantics, we are able to define the notion of boundedness for answer set programming. We prove that boundedness coincides with the notions of recursion-free and loop-free under program equivalence, and is also equivalent to first-order definability of answer set programs on arbitrary structu...

It has been known for a long time that intuitionistically equivalent formulas have the same stable models. We extend this theorem to propositional formulas with infinitely long conjunctions and disjunctions and show how to apply this generalization to proving properties of aggregates in answer set programming.

Article history: Received 15 August 2009 Received in revised form 7 July 2010 Accepted 10 February 2011 Available online 15 March 2011