Action Language BC+
This work addresses a formal modeling problem for researchers in knowledge representation and AI, but it is incremental as it builds on existing action languages and ASP advancements.
The authors tackled the gap between action languages and modern Answer Set Programming (ASP) by proposing BC+, a new action language that integrates advanced ASP constructs like choice rules and aggregates, enabling it to encompass features of existing languages such as B, C, C+, and BC, and they implemented it by extending the cplus2asp system.
Action languages are formal models of parts of natural language that are designed to describe effects of actions. Many of these languages can be viewed as high level notations of answer set programs structured to represent transition systems. However, the form of answer set programs considered in the earlier work is quite limited in comparison with the modern Answer Set Programming (ASP) language, which allows several useful constructs for knowledge representation, such as choice rules, aggregates, and abstract constraint atoms. We propose a new action language called BC+, which closes the gap between action languages and the modern ASP language. The main idea is to define the semantics of BC+ in terms of general stable model semantics for propositional formulas, under which many modern ASP language constructs can be identified with shorthands for propositional formulas. Language BC+ turns out to be sufficiently expressive to encompass the best features of other action languages, such as languages B, C, C+, and BC. Computational methods available in ASP solvers are readily applicable to compute BC+, which led to an implementation of the language by extending system cplus2asp.