We study the problem of generalizing from a finite sample to a language taken from a
predefined language class. The two language classes we consider are subsets of the …

Partially ordered NFAs (poNFAs) are NFAs where cycles occur only in the form of self-loops.
A poNFA is universal if it accepts all words over its alphabet. Deciding universality is PSpace …

While the migration from DTD to XML Schema was driven by a need for increased
expressivity and flexibility, the latter was also significantly more complex to use and …

We prove that minimizing finite automata is NP-hard for almost all classes of automata that
extend the class of deterministic finite automata. More specifically, we show that …

We consider the determinism checking of XML Schema content models, as required by the
W3C Recommendation. We argue that currently applied solutions have flaws and make …

Discovering a concise schema from given XML documents is an important problem in XML
applications. In this paper, we focus on the problem of learning an unordered schema from a …

We investigate the problem to decide for DFAs, NFAs and regular expressions whether they
describe deterministic regular languages. For DFAs with limited alphabet size we show the …

We study the descriptional complexity of regular languages that are definable by
deterministic regular expressions, ie, we examine worst-case blow-ups in size when …

A distributed XML document is an XML document that spans several machines or Web
repositories. We assume that a distribution design of the document tree is given, providing …

We investigate the complexity of deciding whether a given regular language can be defined
with a deterministic regular expression. Our main technical result shows that the problem is …