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 propose an algorithm that tests membership for regular expressions and show that the algorithm is correct. This algorithm is written in the style of a sequent proof system. The...
We explore the natural question of whether all NP-complete problems have a common restriction under which they are polynomially solvable. More precisely, we study what languages a...
Regular Expressions (REs) form the basis of most XML type languages, such as DTDs, XML Schema types, and XDuce types (Thompson et al. 2004; Hosoya and Pierce 2003). In this contex...