(computing) Any function that uses recursion and can call itself until a certain condition is met

(mathematics, complex analysis, algebraic geometry) Any function expressible as the quotient of two (coprime) polynomials (and which thus has poles at a finite, discrete set of points which are the roots of the denominator).

(physics) A function which describes the intensity of scattered radiation in any given direction

(computing) A function used in an operating system that is not available to application programs.

(mathematics) Any function whose range is n-dimensional

(algebra, logic, computing) Any function based on the operations AND, OR and NOT, and whose elements are from the domain of Boolean algebra

(mathematical analysis) Any smooth (infinitely differentiable) function f, defined on an open set D⊆ℂ( textit or⊆ℝ), whose value in some neighbourhood of any given point x_0∈D is given by the Taylor series ∑ₙ₌₀ ᪲(f⁽ⁿ⁾(x_0))/(n!)(x-x_0)ⁿ.

(mathematics) A transformation of the complex plane associated with fluid flow / (physics) The equation used to express Helmholtz free energy

(mathematics) Any function (polynomial) whose greatest exponent is 3.

(mathematics) The branch of mathematics dealing with infinite-dimensional vector spaces, whose elements are actually functions, as well as generalizations such as Banach spaces and Hilbert spaces.