The Power of Nondeterminism in Polynomial-Size Bounded-Width Branching Programs

Nondeterministic branching programs introduced by Meinel (1986) proved to be an interesting computational tool for describing higher complexity classes (Meinel 1988). Investigation of the power of nondeterminism in the case of bounded-width nondeterministic branching programs yields the following results: 1.1-time-only-nondeterministic, polynomial-size, and bounded-width branching programs are no more powerful than (ordinary) polynomial-size and bounded-width branching programs;2.k-times-only-nondeterministic, polynomial-size, and bounded-width branching programs, (k > 1), are as powerful as nondeterministic, polynomial-size, and unbounded-width branching programs.That is, Pbw?n1BP = NC1 and Pbw?nkBP = NPpoly, k > 1.