Expressibility in Σ 11


Inspired by Fagin’s result that NP = Σ11, we have developed a partial framework to investigate expressibility inside Σ11 so as to have a finer look into NP . The framework uses interesting combinatorics derived from second-order Ehrenfeucht-Fräıssé games and the notion of game types. Some of the results that have been proven within this framework are: (1… (More)


Cite this paper

@inproceedings{Gomaa2007ExpressibilityI, title={Expressibility in Σ 11}, author={Walid Gomaa}, year={2007} }