We introduce the set of definable restricted complex powers for expansions of the real field and calculate it explicitly for expansions of the real field itself by collections of restricted complex powers. We apply this computation to establish a classification theorem for expansions of the real field by families of locally closed trajectories of linear vector fields.

We introduce the notion of R-analytic functions. These are definable in an o-minimal expansion of a real closed field R and are locally the restriction of a K-differentiable function where K=R[-1]\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K=R[\sqrt{-1}]$$\end{document} is the algebraic closure of R. The class of these functions in this general setting exhibits the nice properties of real analytic functions. We also define strongly R-analytic functions. These are globally the restriction of a K-differentiable function. We show that (...) in arbitrary models of important o-minimal theories strongly R-analytic functions abound and that the concept of analytic cell decomposition can be transferred to non-standard models. (shrink)

We show that if is not in the field generated by α1,…,αn, then no restriction of the function xβ to an interval is definable in . We also prove that if the real and imaginary parts of a complex analytic function are definable in Rexp or in the expansion of by functions xα, for irrational α, then they are already definable in . We conclude with some conjectures and open questions.