On the Converse Theorem of Approximation in Various Metrics for Nonperiodic Functions
نویسندگان
چکیده
A converse theorem of approximation in various metrics for 2π periodic functions of several variables was proved in [5]. We prove the theorem of representation for the derivative of a function, and then the analogous converse theorem for nonperiodic functions defined on the space R. In this way we generalize and improve the results from [4, 6.4]. As usually we say that f(x1, . . . , xn) ∈ Lp(R ), 1 6 p < ∞ if
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