Title
Testing juntas nearly optimally
Abstract
A function on n variables is called a k-junta if it depends on at most k of its variables. In this article, we show that it is possible to test whether a function is a k-junta or is "far" from being a k-junta with O(kε + k log k ) queries, where epsilon is the approximation parameter. This result improves on the previous best upper bound of O (k3/2)ε queries and is asymptotically optimal, up to a logarithmic factor. We obtain the improved upper bound by introducing a new algorithm with one-sided error for testing juntas. Notably, the algorithm is a valid junta tester under very general conditions: it holds for functions with arbitrary finite domains and ranges, and it holds under any product distribution over the domain. A key component of the analysis of the new algorithm is a new structural result on juntas: roughly, we show that if a function f is "far" from being a k-junta, then f is "far" from being determined by k parts in a random partition of the variables. The structural lemma is proved using the Efron-Stein decomposition method.
Year
DOI
Venue
2009
10.1145/1536414.1536437
STOC
Keywords
Field
DocType
general condition,efron-stein decomposition method,arbitrary finite domain,approximation parameter,asymptotically optimal,structural lemma,new algorithm,k part,new structural result,k log k,property testing,algorithms,upper bound,decomposition method
Discrete mathematics,Combinatorics,Property testing,Upper and lower bounds,Decomposition method (constraint satisfaction),Logarithm,Partition (number theory),Asymptotically optimal algorithm,Lemma (mathematics),Mathematics
Conference
ISSN
Citations 
PageRank 
0737-8017
30
1.00
References 
Authors
14
1
Name
Order
Citations
PageRank
Eric Blais128622.49