Self-improved gaps almost everywhere for the agnostic approximation of monomials

  • Authors:
  • Richard Nock;Frank Nielsen

  • Affiliations:
  • Ceregmia-UFR DSE, Université des Antilles-Guyane, Campus de Schoelcher, BP 7209, 97275 Schoelcher, Martinique, France;SONY CS Labs (FRL), 3-14-13 Higashi Gotanda, Shinagawa-Ku, Tokyo 141-0022, Japan

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2007

Quantified Score

Hi-index 5.23

Visualization

Abstract

Given a learning sample, we focus on the hardness of finding monomials having low error, inside the interval bounded below by the smallest error achieved by a monomial (the best rule), and bounded above by the error of the default class (the poorest rule). It is well-known that when its lower bound is zero, it is an easy task to find, in linear time, a monomial with zero error. What we prove is that when this bound is not zero, regardless of the location of the default class in (0,1/2), it becomes a huge complexity burden to beat significantly the default class. In fact, under some complexity-theoretical assumptions, it may already be hard to beat the trivial approximation ratios, even when relaxing the time complexity constraint to be quasi-polynomial or sub-exponential. Our results also hold with uniform weights over the examples.