Non-monotonic Temporal Logics for Goal Specification

Chitta Baral, Jicheng Zhao

One of the main ways to specify goals of agents is to use temporal logics. Most existing temporal logics are monotonic. However, in representing goals of agents, we often require that goals be changed non-monotonically. For example, the initial goal of the agent may be to be always in states where p is true. The agent may later realize that under certain conditions (exceptions) it is ok to be in states where p is not true. In this paper, we propose a simple extension of LTL, which we call N-LTL, that allows non-monotonic specification of goals. We study properties of N-LTL. We also consider a translation from N-LTL to logic programs and study the relationship between N-LTL and logic programs.