Efficient asymmetric inclusion between regular expression types

The inclusion of Regular Expressions (REs) is the kernel of any type-checking algorithm for XML manipulation languages. XML applications would benefit from the extension of REs with interleaving and counting, but this is not feasible in general, since inclusion is EXPSPACE-complete for such extended REs. In [9] we introduced a notion of "conflictfree REs", which are extended REs with excellent complexity behaviour, including a cubic inclusion algorithm [9] and linear membership [10]. Conflict-free REs have interleaving and counting, but the complexity is tamed by the "conflict-free" limitations, which have been found to be satisfied by the vast majority of the content models published on the Web. However, a type-checking algorithm needs to compare machine-generated subtypes against human-defined supertypes. The conflict-free restriction, while quite harmless for the humandefined supertype, is far too restrictive for the subtype. We show here that the PTIME inclusio...

• Type: Conference
• Year: 2009
• Where: ICDT
• Authors: Dario Colazzo, Giorgio Ghelli, Carlo Sartiani
• Keywords: Conflict-free REs, Cubic Inclusion Algorithm, Database, Extended Res, ICDT 2009