Non-Monotonic Spatial Reasoning with Answer Set Programming Modulo
  Theories
  The systematic modelling of dynamic spatial systems is a key requirement in a
wide range of application areas such as commonsense cognitive robotics,
computer-aided architecture design, and dynamic geographic 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 turning tight ASPMT instances into Satisfiability 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. Spatial reasoning is performed by encoding 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 contemporary spatial reasoning systems both within and outside the
context of logic programming. ASPMT(QS) is currently the only existing system
that is capable of reasoning about indirect spatial effects (i.e., addressing
the ramification problem), and integrating geometric and qualitative spatial
information within a non-monotonic spatial reasoning context.
  This paper is under consideration for publication in TPLP.
