Title
Counting paths in planar width 2 branching programs
Abstract
We revisit the problem of counting paths in width-2 planar branching programs. We show that this is hard for Boolean NC1 under ACC0[5] reductions, completing a proof strategy outlined in [3]. On the other hand, for several restricted instances of width-2 planar branching programs, we show that the counting problem is TC0-complete. We also show that non-planar width-2 programs can be planarized in AC0[2]. Using the equivalence of planar width-2 programs with the reduced-form representation of positive rationals, we show that the evaluation problem for this representation in the Stern-Brocot tree is also NC1 hard. In contrast, the evaluation problem in the continued fraction representation is in TC0.
Year
Venue
Keywords
2012
CATS
proof strategy,planar width,restricted instance,evaluation problem,continued fraction representation,width-2 program,boolean nc1,stern-brocot tree,width-2 planar,positive rational,reduced-form representation
Field
DocType
Citations 
Discrete mathematics,Rational number,Combinatorics,Counting problem,ACC0,Planar,Equivalence (measure theory),Mathematics,Branching (version control)
Conference
2
PageRank 
References 
Authors
0.37
12
3
Name
Order
Citations
PageRank
Meena Mahajan168856.90
Nitin Saurabh253.81
Karteek Sreenivasaiah3135.30