Skip to main content
4 events
when toggle format what by license comment
May 9, 2013 at 16:24 comment added BS. No, because modifying the signum function, say on [-1,1], to render it continuous (or even smooth), would just add an $L^1$ function to it, hence a $C_0$ function to its Fourier transform. On the other hand continuous [positive definite][1] functions on $\mathbb{R}$ are exactly the Fourier transforms of finite positive measures, by Bochner's theorem. [1]: en.wikipedia.org/wiki/Positive-definite_function
May 9, 2013 at 16:04 comment added Matthias Ludewig I suppose, continuity of the function does not help either?
May 9, 2013 at 15:38 vote accept Matthias Ludewig
May 9, 2013 at 14:36 history answered BS. CC BY-SA 3.0