Functions continuous on curves in o-minimal structures

Janak Ramakrishnan

Published 2009-02-26, updated 2011-04-21Version 2

We give necessary and sufficient conditions on a non-oscillatory curve in an o-minimal field such that, for any bounded definable function, the germ of the function on an initial segment of the curve can be continuously extended to a closed definable set. This situation is translated into a question about types: What are the conditions on an $n$-type such that, for any bounded definable function, there is a definable set containing the type on which the function is continuous, and can be extended continuously to the set's closure? All such types are definable, and we give the precise conditions that are equivalent to existence of a desired definable set.