Shape conjecture for Fourier transforms of extremal functions

Let φ\varphi be a solution of the Paley–Wiener extremal problem, and let φ^\widehat{\varphi} denote its Fourier transform. Fourier-transform shape conjecture. The function φ^\widehat{\varphi} is nonnegative. Moreover,

(a) if 0<p<20<p<2, then φ^\widehat{\varphi} is decreasing on (0,π)(0,\pi) and φ^(ξ)0\widehat{\varphi}(\xi)\to0 as ξπ\xi\to\pi^-;

(b) if 2<p<2<p<\infty, then φ^\widehat{\varphi} is increasing on (0,π)(0,\pi) and φ^(ξ)\widehat{\varphi}(\xi)\to\infty as ξπ\xi\to\pi^-. The source motivates this from the resemblance of the extremal functions to explicit model functions.

Sources & referencesView supporting material

Primary source

Ole Fredrik Brevig, Andrés Chirre, Joaquim Ortega-Cerdà and Kristian Seip, “Point evaluation in Paley–Wiener spaces”, arXiv:2210.13922 (2023).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.