Circuits on cylinders

Abstract.

We consider the computational power of constant width polynomial size cylindrical circuits and nondeterministic branching programs. We show that every function computed by a ${\mathbf{\Pi }}_{\mathbf{2}} \; \circ \;{\mathbf{MOD}}\; \circ \;{\mathbf{AC}}{^0 }$ circuit can also be computed by a constant width polynomial size cylindrical nondeterministic branching program (or cylindrical circuit) and that every function computed by a constant width polynomial size cylindrical circuit belongs to ACC ⁰.