The systematic modelling of dynamic spatial systems (9 )i s a key requirement in a wide range of application areas such as comonsense cognitive robotics, computer-aided architecture design, dynamic geo- graphic information systems. We present ASPMT(QS), a novel approach and fully-implemented prototype for non-monotonic spatial reasoning — a crucial requirement within dynamic spatial systems- based on Answer Set Programming Modulo Theories (ASPMT). ASPMT(QS) consists of a (qualitative) spatial representation module (QS) and a method for turn- ing tight ASPMT instances into Sat Modulo Theories (SMT) instances in order to compute stable models by means of SMT solvers. We formalise and implement concepts of default spatial reasoning and spatial frame axioms using choice formulas. Spatial reasoning is performed by encod- ing spatial relations as systems of polynomial constraints, and solving via SMT with the theory of real nonlinear arithmetic. We empirically evaluate ASPMT(QS) in comparison with other prominent contempo- rary spatial reasoning systems. Our results show that ASPMT(QS) is the only existing system that is capable of reasoning about indirect spa- tial effects (i.e. addressing the ramification problem), and integrating geometric and qualitative spatial information within a non-monotonic spatial reasoning context.
['Przemyslaw Andrzej Walega', 'Mehul Bhatt', 'Carl P. L. Schultz']
ASPMT(QS): Non-Monotonic Spatial Reasoning with Answer Set Programming Modulo Theories