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In mathematics, the Nörlund–Rice integral, sometimes called Rice's method, relates the ''n''th forward difference of a function to a line integral on the complex plane. As such, it commonly appears in the theory of finite differences, and also has been applied in computer science and graph theory to estimate binary tree lengths. It is named in honour of Niels Erik Nørlund and Stephen O. Rice. Nørlund's contribution was to define the integral; Rice's contribution was to demonstrate its utility by applying saddle-point techniques to its evaluation. ==Definition== The ''n''th forward difference of a function ''f''(''x'') is given by : where is the binomial coefficient. The Nörlund–Rice integral is given by : where ''f'' is understood to be meromorphic, α is an integer, , and the contour of integration is understood to circle the poles located at the integers α, ..., ''n'', but none of the poles of ''f''. The integral may also be written as : where ''B''(''a'',''b'') is the Euler beta function. If the function is polynomially bounded on the right hand side of the complex plane, then the contour may be extended to infinity on the right hand side, allowing the transform to be written as : where the constant ''c'' is to the left of α. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Nörlund–Rice integral」の詳細全文を読む スポンサード リンク
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