E-RES: A System for Reasoning about Actions, Events and Observations
  E-RES is a system that implements the Language E, a logic for reasoning about
narratives of action occurrences and observations. E's semantics is
model-theoretic, but this implementation is based on a sound and complete
reformulation of E in terms of argumentation, and uses general computational
techniques of argumentation frameworks. The system derives sceptical
non-monotonic consequences of a given reformulated theory which exactly
correspond to consequences entailed by E's model-theory. The computation relies
on a complimentary ability of the system to derive credulous non-monotonic
consequences together with a set of supporting assumptions which is sufficient
for the (credulous) conclusion to hold. E-RES allows theories to contain
general action laws, statements about action occurrences, observations and
statements of ramifications (or universal laws). It is able to derive
consequences both forward and backward in time. This paper gives a short
overview of the theoretical basis of E-RES and illustrates its use on a variety
of examples. Currently, E-RES is being extended so that the system can be used
for planning.
