Handling Termination in a Logical Language for Active Rules
Bertram Ludäscher, Georg Lausen
Abstract. Statelog is a Datalog extension
integrating the declarative semantics of deductive rules with
the possiblity to define updates in the style of active and
production rules. The language is surprisingly simple, yet
captures many essential features of active rules. After
reviewing the basics of active rules, production rules, and
deductive rules, we elaborate on the problem of handling rule
termination in the context of Statelog: It is undecidable
whether a Statelog program terminates for all databases,
and PSPACE-complete for a given database. The
latter can be accomplished within the logical language:
for every Statelog program P, there is a terminating
program P' which decides for any given database D,
whether P u D terminates.