Many reasoning problems in logic and constraint satisfaction have been shown to be exponential only in the treewidth of their interaction graph: a graph which captures the structural interactions among variables in a problem. It has long been observed in both logic and constraint satisfaction, however, that problems may be easy even when their treewidth is quite high. To bridge some of the gap ...

Example and counterexample relations are important during the process of database design in order to guide the database designer towards specifying a correct set of integrity constraints; we assume that the constraints are speciied in terms of functional dependencies (FDs). We propose a stochastic algorithm which evolves an example relation that satisses a set of FDs from a random relation of a...

We introduce the notion of functional dependencies of abstract interpretations relatively to a binary operator of composition. Functional dependencies are obtained by a functional composition of abstract domains, and provide a systematic approach to construct new abstract domains. In particular, we study the case of autodependencies, namely monotone operators on a given abstract domain. Under s...

In Database Theory, Multivalued Dependencies are the main tool to define the Fourth Normal Form and, as such, their inference problem has been deeply studied; two related notions appearing in that study are a syntactical analog in propositional logic and a restriction that maintains to this logic the same relationship as Functional Dependencies do to Horn logic. We present semantic, lattice-the...

Functional dependencies [4] and multivalued dependencies [5,11] are important, widely-studied constraints on databases. A fundamental issue in database theory is the question of determining whether or not a given set of dependencies (in our case, functional and multivalued dependencies) logically implies another given dependency. We provide a simple and elegant set-theoretic characterization fo...

We study multivalued dependencies, as well as the propositional formulas whose deduction calculus parallels that of multivalued dependencies, and the variant known as degenerated multivalued dependencies. For each of these sorts of expressions, we provide intrinsic characterizations in purely semantic terms. They naturally generalize similar properties of functional dependencies or Horn clauses.

Received Apr 11, 2017 Revised May 5, 2017 Accepted May 24, 2017 Conditional functional dependencies (CFDs) have been used to improve the quality of data, including detecting and repairing data inconsistencies. Approximation measures have significant importance for data dependencies in data mining. To adapt to exceptions in real data, the measures are used to relax the strictness of CFDs for mor...

In this paper we consider tabulated data or relations in a data base __I__-_ system which are constrained by functional dependencies. This implies that the data in certain columns of each table is determined by the data contained in some other columns. The problem we address is that of the computation of the size of projections of the data on a subset of the columns. This may be viewed as the p...

XML is becoming a prevalent format and defacto standard for data exchange in many applications. While traditionally, lots of data are stored and managed in relational databases. There is an urgent need to research some efficient methods to convert these data stored in relational databases to XML format when integrating and exchanging these data in XML format. The semantics of XML schemas are cr...