  In this paper we present a novel rule-based approach for Runtime Verification
of FLTL properties over finite but expanding traces. Our system exploits Horn
clauses in implication form and relies on a forward chaining-based monitoring
algorithm. This approach avoids the branching structure and exponential
complexity typical of tableaux-based formulations, creating monitors with a
single state and a fixed number of rules. This allows for a fast and scalable
tool for Runtime Verification: we present the technical details together with a
working implementation.
