This survey gives an overview of formal results on the XML query language XPath. We
identify several important fragments of XPath, focusing on subsets of XPath 1.0. We then …

We give semantic characterizations of the expressive power of navigational XPath (aka Core
XPath) in terms of first order logic. XPath can be used to specify sets of nodes and sets of …

We investigate the complexity of the model checking problem for hybrid logics. We provide
model checking algorithms for various hybrid fragments and we prove PSPACE …

We live in the Information Age, where most of the personal, business, and administrative
data are collected and managed electronically. However, poor data quality may affect the …

We consider unranked trees that have become an active subject of study recently due to
XML applications, and characterize commonly used fragments of first-order (FO) and …

The large volume and nature of data available to the casual users and programs motivate
the increasing interest of the database community in studying flexible and efficient …

Large amounts of data are collected by public administrations and healthcare organizations,
the integration of the data scattered in several information systems can facilitate the …

Büchi automata have applications in formal verification, eg, in deciding whether a system
satisfies given properties. We provide a definition of Büchi automata based on first order …

The branching-time temporal logic CTL is useful for specifying systems that change over
time and involve quantification over possible futures. Here we present a resolution calculus …

Close relationships between XML navigation and temporal logics have been discovered
recently, in particular between logics LTL and CTL* and XPath navigation, and between the …