Introduction to the special issue on quantified CSPs and QBF

The July 2008 issue of Springer Science + Business Media introduced Constraint satisfaction problems (CSPs) and quantified Boolean formulae (QBF). Bodirsky and Chen studied the relatively quantified constraint satisfaction problem (RQCSP), a subclass of the QCSP in which the values for each individual variable can be arbitrarily restricted. Stynes and Brown proposed two families of value ordering heuristics for QCSPs. The first is inspired by adversarial search while the second attempts to reduce the size of the universal variables' domains. Egly, Seidl and Woltran described a QBF solver, called 'qpro', which can handle QBFs expressed not only in prenex conjunctive normal form, but in any arbitrary way. Pulina and Tacchella studied the problem of engineering a robust solver for QBF.