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Timeline for Composition of Riesz potentials

Current License: CC BY-SA 4.0

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Nov 13, 2018 at 19:00 history edited Piotr Hajlasz CC BY-SA 4.0
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May 19, 2018 at 13:16 vote accept Piotr Hajlasz
Mar 28, 2018 at 9:49 answer added Mateusz Kwaśnicki timeline score: 3
Mar 27, 2018 at 23:38 comment added Piotr Hajlasz @MateuszKwaśnicki A very nice argument. You should post it as an answer.
Mar 22, 2018 at 22:38 comment added Mateusz Kwaśnicki There are many ways to prove this fact. The most elementary one that I know involves the subordination formula $u_\alpha(x) = (\Gamma(\alpha/2))^{-1} \int_0^\infty t^{\alpha/2-1} g_t(x) dx$ (where $g_t(x) = (4 \pi t)^{-n/2} e^{-|x|^2/(4t)}$ is the Gauss–Weierstrass kernel; this formula follows easily from the gamma integral), together with Fubini and $g_t * g_s = g_{t+s}$. Similar argument is typically used to show that the Fourier transform of $u_\alpha$ is indeed $|\xi|^{-\alpha}$ (without multiplication by a constant).
S Mar 22, 2018 at 21:53 answer added Piotr Hajlasz timeline score: 3
S Mar 22, 2018 at 21:53 history asked Piotr Hajlasz CC BY-SA 3.0