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Efficient low-degree polynomial interpolation 11/29/2017

Speaker: Alexander Barg, University of Maryland

Abstract: Let f(x) be a polynomial of degree less than k over a finite field F_q. Its value at any given point a in F_q can be found once we know its values at any k other points a_i. We consider the problem of finding f(a) by observing some partial information about the values of f(x) at d > k points, i.e., some functions g_i(a_i), i=j_1, \ldots ,j_d. We present a construction that gives an optimal solution of this problem (we will discuss the meaning of optimality along the way). The construction relies on specially designed subfields of F_q. This problem is known in coding theory as the repair problem of Reed-Solomon codes, and we will use coding theoretic language in the description of the solution. Based on recent joint works with Itzhak Tamo and Min Ye.