Gelfand numbers and widths

نویسندگان

  • David E. Edmunds
  • Jan Lang
چکیده

In general, the Gelfand widths cn(T ) of a map T between Banach spaces X and Y are not equivalent to the Gelfand numbers cn(T ) of T . We show that cn(T ) = cn(T ) (n ∈ N) provided that X and Y are uniformly convex and uniformly smooth, and T has trivial kernel and dense range. c ⃝ 2012 Elsevier Inc. All rights reserved.

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عنوان ژورنال:
  • Journal of Approximation Theory

دوره 166  شماره 

صفحات  -

تاریخ انتشار 2013