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In potential theory, a discipline within applied mathematics, the Furstenberg boundary is a notion of boundary associated with a group. It is named for Harry Furstenberg, who introduced it in a series of papers beginning in 1963 (in the case of semisimple Lie groups). The Furstenberg boundary, roughly speaking, is a universal moduli space for the Poisson integral, expressing a harmonic function on a group in terms of its boundary values. ==Motivation== A model for the Furstenberg boundary is the hyperbolic disc . The classical Poisson formula for a bounded harmonic function on the disc has the form : where ''m'' is the Haar measure on the boundary and ''P'' is the Poisson kernel. Any function ''f'' on the disc determines a function on the group of Möbius transformations of the disc by setting . Then the Poisson formula has the form : This function is then harmonic in the sense that it satisfies the mean-value property with respect to a measure on the Möbius group induced from the usual Lebesgue measure of the disc, suitably normalized. The association of a bounded harmonic function to an (essentially) bounded function on the boundary is one-to-one. 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「Furstenberg boundary」の詳細全文を読む スポンサード リンク
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