In harmonic analysis, the restriction conjecture, also known as the Fourier restriction conjecture, is a conjecture about the behaviour of the Fourier transform on curved hypersurfaces. [1] [2] It was first hypothesized by Elias Stein. [3] The conjecture states that two necessary conditions needed to solve a problem known as the restriction problem in that scenario are also sufficient. [2] [3]
The restriction conjecture is closely related to the Kakeya conjecture, Bochner-Riesz conjecture and the local smoothing conjecture. [4] [5]