Existing web search engines provide users with the ability to query an off-line database of indices in order to decide on an entry point for further manual navigation. Results are...
Since the birth of XML, the processing of XML query languages like XQuery/XQueryP has been widely researched in the academic and industrial communities. Most of the approaches con...
A propositional system of modal logic is second-order if it contains quantifiers p and p, which, in the standard interpretation, are construed as ranging over sets of possible worl...
As the eXtensible Markup Language (XML) is about to emerge as a new standard for databases, the problem of providing solid logical grounds for XML query languages arises. For the ...
We study relations on trees defined by first-order constraints over a vocabulary that includes the tree extension relation Ì Ì ¼, holding if and only if every branch of Ì ex...