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In mathematics, the Barnes G-function ''G''(''z'') is a function that is an extension of superfactorials to the complex numbers. It is related to the Gamma function, the K-function and the Glaisher–Kinkelin constant, and was named after mathematician Ernest William Barnes.〔E. W. Barnes, "The theory of the G-function", ''Quarterly Journ. Pure and Appl. Math.'' 31 (1900), 264–314.〕 Up to elementary factors, it is a special case of the double gamma function. Formally, the Barnes ''G''-function is defined in the following Weierstrass product form: : where is the Euler–Mascheroni constant, exp(''x'') = ''e''''x'', and ∏ is capital pi notation. ==Functional equation and integer arguments== The Barnes ''G''-function satisfies the functional equation : with normalisation ''G''(1) = 1. Note the similarity between the functional equation of the Barnes G-function and that of the Euler Gamma function: : The functional equation implies that ''G'' takes the following values at integer arguments: : (in particular, ) and thus : where denotes the Gamma function and ''K'' denotes the K-function. The functional equation uniquely defines the G function if the convexity condition: is added.〔M. F. Vignéras, ''L'équation fonctionelle de la fonction zêta de Selberg du groupe mudulaire SL'', Astérisque 61, 235–249 (1979).〕 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「Barnes G-function」の詳細全文を読む スポンサード リンク
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