Compactification of L(Q)

In this paper we extend the usual notion of model (as a structure) to the m ore general notion of Cauchy Sequence of Structures in a similar way as rat ionals are extending to real numbers by means of Cauchy sequences of ration als. We show that the structure space St(tau) is dense in the complete spac e CSt(tau) of Cauchy sequences of structures and that CSt(tau) is compact i n the (topo)logical sense.