Title
An Exponential Lower Bound for Homogeneous Depth Four Arithmetic Formulas
Abstract
We show here a 2Ω(√d ⋅ log N) size lower bound for homogeneous depth four arithmetic formulas. That is, we give an explicit family of polynomials of degree d on N variables (with N = d3 in our case) with 0, 1-coefficients such that for any representation of a polynomial f in this family of the form f = Σi ∏j Qij, where the Qij's are homogeneous polynomials (recall that a polynomial is said to be homogeneous if all its monomials have the same degree), it must hold that ∑i, j (Number of monomials of Qij)) ≥2Ω(√d ⋅log N). The above mentioned family, which we refer to as the Nisan-Wigderson design-based family of polynomials, is in the complexity class VNP. Our work builds on recent lower bound results [1], [2], [3], [4], [5] and yields an improved quantitative bound as compared to the quasi-polynomial lower bound from an earlier work of the same authors and the NΩ(log log N) lower bound in the independent work of [7].
Year
DOI
Venue
2014
10.1109/FOCS.2014.15
Foundations of Computer Science
Keywords
Field
DocType
circuit complexity,0,1-coefficients,2Ω(√d·log N) size lower bound,Nisan-Wigderson design-based family,complexity class VNP,homogeneous depth arithmetic formulas,homogeneous polynomials,Arithmetic circuits,lower bounds,shifted partial derivatives
Log-log plot,Complexity class,Discrete mathematics,Binary logarithm,Combinatorics,Exponential function,Polynomial,Homogeneous,Upper and lower bounds,Arithmetic,Monomial,Mathematics
Conference
Volume
Issue
ISSN
46
1
0272-5428
Citations 
PageRank 
References 
21
0.75
27
Authors
4
Name
Order
Citations
PageRank
Neeraj Kayal126319.39
Nutan Limaye213420.59
Chandan Saha322716.91
Srikanth Srinivasan413221.31