## Extensions, Automorphisms, and Definability

by
Robert I. Soare

Venue: | CONTEMPORARY MATHEMATICS |

### BibTeX

@MISC{Soare_extensions,automorphisms,,

author = {Robert I. Soare},

title = {Extensions, Automorphisms, and Definability},

year = {}

}

### OpenURL

### Abstract

This paper contains some results and open questions for automorphisms and definable properties of computably enumerable (c.e.) sets. It has long been apparent in automorphisms of c.e. sets, and is now becoming apparent in applications to topology and dierential geometry, that it is important to know the dynamical properties of a c.e. set We , not merely whether an element x is enumerated in We but when, relative to its appearance in other c.e. sets. We present here