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Volume 7 (2011) Article 1 pp. 1-18
Noisy Interpolating Sets for Low-Degree Polynomials
Received: September 4, 2009
Published: February 12, 2011
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Keywords: polynomial interpolation, error-correcting codes
ACM Classification: F.2.2
AMS Classification: 68P30, 68Q25

Abstract: [Plain Text Version]

\newcommand{\F}{{\mathbb F}} A Noisy Interpolating Set (NIS) for degree-d polynomials is a set S \subseteq \F^n, where \F is a finite field, such that any degree-d polynomial q \in \F[x_1,\ldots,x_n] can be efficiently interpolated from its values on S, even if an adversary corrupts a constant fraction of the values. In this paper we construct explicit NIS for every prime field \F_p and any degree d. Our sets are of size O(n^d) and have efficient interpolation algorithms that can recover q from a fraction \exp(-O(d)) of errors.

Our construction is based on a theorem which roughly states that if S is a NIS for degree-1 polynomials then d \cdot S= \{ a_1 + \ldots + a_d \,|\, a_i \in S\} is a NIS for degree-d polynomials. Furthermore, given an efficient interpolation algorithm for S, we show how to use it in a black-box manner to build an efficient interpolation algorithm for d \cdot S.

As a corollary we obtain an explicit family of punctured Reed-Muller codes (codes that are restrictions of a Reed-Muller code to a subset of the coordinates) which are good codes and have an efficient decoding algorithm against a constant fraction of errors. To the best of our knowledge, even the existence of punctured Reed-Muller codes that are good codes was not previously known.