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Schoenberg's Problem on Positive Definite Functions

Alexander Koldobsky
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Abstract

If $n \ge 3$, $q>2$ and $β> 0$ then the function $\exp(-(|x_1|^q+|x_2|^q+\dots+|x_n|^q)^{β/q})$\ is not positive definite. This result gives an answer to a question posed by I.J.~Schoenberg in 1938. This text is an authorized English translation of the paper published in Russian in Algebra and Analysis 3(1991), \#3, p.78--85.

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Alexander Koldobsky. 1992-10-19. Schoenberg's Problem on Positive Definite Functions. https://arxiv.org/abs/math/9210207

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