Ridgelets and the Representation of Mutilated Sobolev Functions
نویسنده
چکیده
We show that ridgelets, a system introduced in [4], are optimal to represent smooth multivariate functions that may exhibit linear singularities. For instance, let {u · x− b > 0} be an arbitrary hyperplane and consider the singular function f(x) = 1{u·x−b>0}g(x), where g is compactly supported with finite Sobolev L2 norm ‖g‖Hs , s > 0. The ridgelet coefficient sequence of such an object is as sparse as if f were without singularity, allowing optimal partial reconstructions. For instance, the n-term approximation obtained by keeping the terms corresponding to the n largest coefficients in the ridgelet series achieves a rate of approximation of order n−s/d; the presence of the singularity does not spoil the quality of the ridgelet approximation. This is unlike all systems currently in use and especially Fourier or wavelet representations.
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عنوان ژورنال:
- SIAM J. Math. Analysis
دوره 33 شماره
صفحات -
تاریخ انتشار 2001