Motivated by the question of how to define an analog of interactive proofs in the setting of logarithmic time- and space-bounded computation, we study complexity classes defined in terms of operators quantifying over oracles. We obtain new characterizations of $\NCe$, $\L$, $\NL$, $\NP$, and $\NSC$ (the nondeterministic version of SC). ... more >>>

The parallel complexity class NC^1 has many equivalent models such as polynomial size formulae and bounded width branching programs. Caussinus et al. \cite{CMTV} considered arithmetizations of two of these classes, #NC^1 and #BWBP. We further this study to include arithmetization of other classes. In particular, we show that counting paths ... more >>>