In mathematics, a Gelfand pair is a pair "(G,K)" consisting of a group "G" and a subgroup "K" (called an Euler subgroup of "G") that satisfies a certain property on restricted representations. The theory of Gelfand pairs is closely related to the topic of spherical functions in the classical theory of special functions, and to the theory of Riemannian symmetric spaces in differential geometry. Broadly speaking, the theory exists to abstract from these theories their content in terms of harmonic analysis and representation theory.