Definitions for "Fourier series"
An infinite series of the form . Such series represent singly periodic meromorphic functions f(z), where f(z+1) = f(z) for all z. There is an extensive theory developed around the properties of such series, having many uses in both theoretical and applied mathematics.
the sum of a series of trigonometric expressions; used in the analysis of periodic functions
an expansion of a periodic function f(x) in terms of an infinite sum of s and cos
Expressions used to fit trend surfaces to spatially distributed variables if the variables are thought to behave in an oscillatory manner across space.