In this paper we study the problem of deciding whether a regular path query over views in data-integration systems can be re-expressed without recursion. The problem becomes chall...
We consider the problem of repairing unranked trees (e.g., XML documents) satisfying a given restriction specification R (e.g., a DTD) into unranked trees satisfying a given targ...
Abstract. We consider policies that are described by regular expressions, finite automata, or formulae of linear temporal logic (LTL). Such policies are assumed to describe situat...
In the classical framework of formal languages, a refinement n is modeled by a substitution and an abstraction by an inverse substitution. These mechanisms have been widely studie...
We consider formulas which, in addition to the symbols in the vocabulary, may use two designated symbols ≺ and + that must be interpreted as a linear order and its associated ad...