Constraint Arithmetic on Real Intervals

Constraint interval arithmetic is a sublanguage of BNR Prolog which o ers a new approach to the old problem of deriving numerical consequences from algebraic models. Since it is simultaneously a numerical computation technique and a proof technique, it bypasses the traditional dichotomy between (numeric) calculation and (symbolic) proofs. This interplay between proof and calculation can be used e ectively to handle practical problems which neither can handle alone. The underlying semantic model is based on the properties of monotone contraction operators on a lattice, an algebraic setting in which xed point semantics take an especially elegant form.