On Lebesgue-type inequalities for greedy approximation

نویسندگان

  • David L. Donoho
  • Michael Elad
  • Vladimir N. Temlyakov
چکیده

We study the efficiency of greedy algorithms with regard to redundant dictionaries in Hilbert spaces. We obtain upper estimates for the errors of the Pure GreedyAlgorithm and the Orthogonal GreedyAlgorithm in terms of the best m-term approximations. We call such estimates the Lebesgue-type inequalities. We prove the Lebesgue-type inequalities for dictionaries with special structure. We assume that the dictionary has a property of mutual incoherence (the coherence parameter of the dictionary is small). We develop a new technique that, in particular, allowed us to get rid of an extra factor m1/2 in the Lebesgue-type inequality for the Orthogonal Greedy Algorithm. © 2007 Elsevier Inc. All rights reserved.

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عنوان ژورنال:
  • Journal of Approximation Theory

دوره 147  شماره 

صفحات  -

تاریخ انتشار 2007