In this paper, we describe the need for intelligent retrieval components in materials information systems. Starting from an object-oriented tool-based retrieval interface, three modules for intelligent query support are presented: WING-GRAPH, a facility allowing for direct manipulation based graphical retrieval exploiting the cognitive abilities involved in graphical thinking and interpretation...

Valued constraint satisfaction problems (VCSPs) are a large class of combinatorial optimisation problems. The computational complexity VCSPs depends on the set allowed cost functions in input. Recently, all for finite sets over domains has been classified. Many natural problems, however, cannot be formulated as domain. We initiate systematic investigation infinite-domain with piecewise linear h...

For any commutative ring R that is not a domain, there is a zerodivisor graph, denoted Γ(R), in which the vertices are the nonzero zero-divisors of R and two distinct vertices x and y are joined by an edge exactly when xy = 0. In [Sm2], Smith characterized the graph structure of Γ(R) provided it is infinite and planar. In this paper, we give a ring-theoretic characterization of R such that Γ(R)...

We systematically investigate the computational complexity of constraint satisfaction problems for constraint languages over an infinite domain. In particular, we study a generalization of the well-established notion of maximal constraint languages from finite to infinite domains. If the constraint language can be defined with an ω-categorical structure, then maximal constraint languages are in...

Constraint satisfaction problems are limited in that their domain values are treated as atomic entities, causing specifications for infinite CSPs to be solver-dependent. ObjectOriented Constraint Satisfaction Problems (OOCSPs) synthesize the object-oriented paradigm with declarative constraints to provide a rich language for describing infinite domains, independent of the solver. This paper int...