  In temporal extensions of Answer Set Programming (ASP) based on linear-time,
the behavior of dynamic systems is captured by sequences of states. While this
representation reflects their relative order, it abstracts away the specific
times associated with each state. However, timing constraints are important in
many applications like, for instance, when planning and scheduling go hand in
hand. We address this by developing a metric extension of linear-time temporal
equilibrium logic, in which temporal operators are constrained by intervals
over natural numbers. The resulting Metric Equilibrium Logic provides the
foundation of an ASP-based approach for specifying qualitative and quantitative
dynamic constraints. To this end, we define a translation of metric formulas
into monadic first-order formulas and give a correspondence between their
models in Metric Equilibrium Logic and Monadic Quantified Equilibrium Logic,
respectively. Interestingly, our translation provides a blue print for
implementation in terms of ASP modulo difference constraints.
