Graça, Daniel2012-04-182012-04-182003AUT: DGR01772;http://hdl.handle.net/10400.1/1039In this paper we are interested in a particular model of analog computation, the General Purpose Analog Computer (GPAC). In particular, we provide more solid foundations for this model and we show that it can be used to introduce a notion of computability for smooth continuous dynamical systems over Rn. We also show that hierarchies over these dynamical systems can be established, thereby defining a notion of relative computability.engconference object