: XML DBMSs require new indexing techniques to efficiently process structural search and full-text search as integrated in XQuery. Much research has been done for indexing XML docu...
We are interested in the expressiveness of constraints represented by general first order formulae, with equality as unique relation symbol and function symbols taken from an infi...
A top-down query processing method for first order deductive databases under the disjunctive well-founded semantics (DWFS) is presented. The method is based upon a characterisation...
We show the decidability of model checking PA-processes against several first-order logics based upon the reachability predicate. The main tool for this result is the recognizabil...
We introduce tree-width for first order formulae , fotw(). We show that computing fotw is fixed-parameter tractable with parameter fotw. Moreover, we show that on classes of formul...