d abstract) T. Eiter G. Gottlob Y. Gurevich Institut fur Informatik Institut fur Informationssysteme EECS Department Universitat Gie en Technische Universitat Wien University of Mi...
We study the Monadic Second Order (MSO) Hierarchy over infinite pictures, that is tilings. We give a characterization of existential MSO in terms of tilings and projections of tili...
It is a well-known result of Fagin that the complexity class NP coincides with the class of problems expressible in existential second-order logic ( 1 1), which allows sentences c...