Hoang Mai Le

Abstract
In this paper, the existence of  $\lim_{n \to \infty} \| f^{(n)} \|^{1/n}_{(p,q)} $ for an arbitrary function $f \in C^{\infty}(\Bbb R) $ such that $  f^{(n)} \in (L_p, l_q), \;  n = 0, 1, \ldots \ $ and the concrete calculation of $\lim_{n \to \infty} \| f^{(n)} \|^{1/n}_{(p,q)}$ are shown.