We prove that any AC0 circuit augmented with {epsilon log^2 n}
MOD_m gates and with a MAJORITY gate at the output, require size
n^{Omega(log n)} to compute MOD_l, when l has a prime
factor not dividing m and epsilon is sufficiently small. We
also obtain that ... more >>>

We obtain a characterization of ACC0 in terms of a natural class of
constant width circuits, namely in terms of constant width polynomial
size planar circuits. This is shown via a characterization of the
class of acyclic digraphs which can be embedded on a cylinder surface
in such a way ... more >>>

We consider the computational power of constant width polynomial
size cylindrical circuits and nondeterministic branching programs.
We show that every function computed by a Pi2 o MOD o AC0 circuit
can also be computed by a constant width polynomial size cylindrical
nondeterministic branching program (or cylindrical circuit) and
that ... more >>>