  In this paper, we investigate an approach to circuit lower bounds via bounded
width circuits. The approach consists of two steps: (i) We convert circuits to
(deterministic or nondeterministic) bounded width circuits. (ii) We prove lower
bounds for the bounded width circuits.
  For the second step, we prove that there is an explicit Boolean function $f$
as follows: If a nondeterministic circuit of size $s$ and width $w$ computes
$f$, then $w = \Omega(\frac{n^4}{4^{\frac{s}{n}}s^3}) - \frac{\log_2 s}{2}$.
For the first step, we give some observations, which include a relation between
conversions to bounded width circuits and a standard pebble game.
