Models of computability of partial functions on the reals

Abstract

<p> Various models of computability of partial functions f on the real numbers are studied: two abstract, based on approximable computation w.r.t high level programming languages; two concrete, based on computable tracking functions on the rationals; and two based on polynomial approximation. It is shown that these six models are equivalent, under the assumptions: (1) the domain of f is a union of an effective sequence of rational open intervals, and (2) f is effectively locally uniformly continuous. This includes the well-known functions of elementary real analysis (rational, exponential, trigonometric, etc., and their inverses) and generalises a previously know equivalence result for total functions on the reals. </p>