The main purpose of this paper is to investigate the characteristics that distinguish spatial databases systems from traditional ones. Guided by the concept of genericity, we give an overview of some well-known data models and query languages of spatial database systems. For spatial databases the concept of genericity, as introduced by Chandra and Harel for classical databases 5], breaks up in ...

The main purpose of this paper is to investigate the characteristics that distinguish spatial databases systems from traditional ones. Hereto, we give an overview of some well-known data models and query languages of spatial database systems. We also investigate the concept of genericity, as introduced by Chandra and Harel for classical databases [6], for spatial databases. Paredaens, Van den B...

A class of r.e. degrees, called the array nonrecursive degrees, previously studied by the authors in connection with multiple permitting arguments relative to r.e. sets, is extended to the degrees in general. This class contains all degrees which satisfy a 00 > (a 0 0) 0 (i.e. a 2 GL 2) but in addition there exist low r.e. degrees which are array nonrecursive (a.n.r.). Many results for GL 2 deg...

Woodin proved the theorem in perhaps 1986 or 1987, using stationary tower forcing and (through the work of Martin and the author) iteration trees. The proof we give here uses only iteration trees. Stationary tower forcing is replaced by “genericity iterations”, as it can be in certain related contexts as well. We believe that the unity of method in the resulting proof gives it some interest. Th...

Aspect-oriented programming languages promise to provide better modularity than pure object-oriented decomposition. A typical benefit of increased modularity is ease of maintenance, evolution and reuse. However, it has been noted by various researchers that many of the first generation aspect languages do not provide the degree of reusability initially hoped for. In this paper, we argue that th...

We compare three notions of genericity of separable metric structures. Our analysis provides a general model theoretic technique of showing that structures are generic in discriptive set theoretic (topological) sense and in measure theoretic sense. In particular, it gives a new perspective on Vershik’s theorems on genericity and randomness of Urysohn’s space among separable metric spaces.

We compare three notions of genericity of separable metric structures. Our analysis provides a general model theoretic technique of showing that structures are generic in descriptive set theoretic (topological) sense and in measure theoretic sense. In particular, it gives a new perspective on Vershik’s theorems on genericity and randomness of Urysohn’s space among separable metric spaces.