Learning intersections and thresholds of halfspaces

  • Authors:
  • Adam R. Klivans;Ryan O'Donnell;Rocco A. Servedio

  • Affiliations:
  • Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA;School of Mathematics, Institute for Advanced Study, Princeton, NJ;Department of Computer Science, Fu Foundation School of Engineering, Applied Sciences, Columbia University, 450 Computer Science Building, 1214 Amsterdam Avenue, Mailcode 0401, New York, NY

  • Venue:
  • Journal of Computer and System Sciences - Special issue on FOCS 2002
  • Year:
  • 2004

Quantified Score

Hi-index 0.00

Visualization

Abstract

We give the first polynomial time algorithm to learn any function of a constant number of halfspaces under the uniform distribution on the Boolean hypercube to within any constant error parameter. We also give the first quasipolynomial time algorithm for learning any Boolean function of a polylog number of polynomial-weight halfspaces under any distribution on the Boolean hypercube. As special cases of these results we obtain algorithms for learning intersections and thresholds of halfspaces. Our uniform distribution learning algorithms involve a novel non-geometric approach to learning halfspaces; we use Fourier techniques together with a careful analysis of the noise sensitivity of functions of halfspaces. Our algorithms for learning under any distribution use techniques from real approximation theory to construct low-degree polynomial threshold functions. Finally, we also observe that any function of a constant number of polynomial-weight halfspaces can be learned in polynomial time in the model of exact learning from membership and equivalence queries.