A mathematical theorem stating that a periodic function f(x) which is reasonably continuous may be expressed as the sum of a series of sine or cosine terms (called the Fourier series), each of which ...

If there's a mathematical idea that applies itself to almost everything in everyday life but is almost unknown outside the scientific world, the Fourier transform has to be the most unsung contender.

THIS important new Cambridge tract is concerned with the modern developments of the mathematical theory of Fourier series. The character of this theory was radically altered during the decade 1900–10 ...