partial function

partial function [′pär·shəl ′fəŋk·shən]

(computer science)

A partial function from a setAto a setBis a correspondence between some subset ofAandBwhich associates with each element of the subset ofAa unique element ofB.

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partial function - A function which is not defined for all arguments of its input type. E.g. f(x) = 1/x if x /= 0. The opposite of a total function. In denotational semantics, a partial function f : D -> C may be represented as a total function ft : D' -> lift(C) where D' is a superset of D and ft x = f x if x in D ft x = bottom otherwise where lift(C) = C U bottom. Bottom (LaTeX \perp) denotes "undefined".