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Can someone please expand on this statement, "if one is counting solutions, inside a given set, to a linear equation, then it is enough, and usually easier, to
by iaf 12y ago
Can someone please expand on this statement, "if one is counting solutions, inside a given set, to a linear equation, then it is enough, and usually easier, to estimate Fourier coefficients of the characteristic function of the set"
- mathgenius 12y agoThe characteristic function of a set is one in the set and zero outside [1]. Take fourier transform of this function. Fourier transform is a linear operator. Turn handle, bingo. [1] http://en.wikipedia.org/wiki/Indicator_function http://en.wikipedia.org/wiki/Indicator_function
- iaf 12y agoAh, I didn't know 'characteristic' function and 'indicator' function were synonyms. Thanks!