Following [the documentation](https://mcdoll.github.io/DispersiveEquations/find/?domain=Verso.Genre.Manual.section&name=Dispersive-equations--The-Fourier-transform-of-a-complex-Gaussian--Sketch-of-the-proof--Step-1___-A-simple-regularity-theorem) show that `x_j u = 0` implies that `u = c δ`. If you are interested in working on this issue please reply here to claim it.
Following the documentation show that
x_j u = 0implies thatu = c δ.If you are interested in working on this issue please reply here to claim it.