View Related Documents

Abstract

The parallel complexity class NC 1 has many equivalent models such as bounded width branching programs. Caussinus et.al [10] 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 in branching programs over visibly pushdown automata has the same power as #BWBP, while counting proof-trees in logarithmic width formulae has the same power as #NC 1. We also consider polynomial-degree restrictions of \sf SCi{\sf SC}^{i} , denoted \sf sSCi{\sf sSC}^{i} , and show that the Boolean class \sf sSC1{\sf sSC}{^1} lies between NC 1 and L, whereas \sf sSC0{\sf sSC}^0 equals \sf NC1{\sf NC}^1 . On the other hand, \sf #\sf sSC0{\sf \#}{\sf sSC}^0 contains #BWBP and is contained in FL, and #sSC 1 contains #NC 1 and is in \sf SC2{\sf SC}^{2} . We also investigate some closure properties of the newly defined arithmetic classes.

Fulltext Preview

Image of the first page of the fulltext document