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Positive definiteness of a family of functions - MaRDI portal

Positive definiteness of a family of functions (Q2396418)

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Positive definiteness of a family of functions
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    Positive definiteness of a family of functions (English)
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    8 June 2017
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    Let \(\rho\) be a norm on \(\mathbb R^n\) and \(w,z\in\mathbb C\). Conditions for \(w, z\) are given for the positive definiteness of the function \(x\mapsto f_{w,z}(\rho(x))\), where \(f_{w,z}(t)=\mathrm{Re}(we^{-zt})\). Some conditions hold for \(\|\cdot\|_1,\;\|\cdot\|_2\) or \(n=2\) only.
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    positive definite functions
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    Bochner's theorem
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