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A hyperbolic geometric graph (HGG) or hyperbolic geometric network (HGN) is special spatial network where nodes are (1) sprinkled according to a probability distribution onto a hyperbolic space of constant negative curvature and (2) an edge between two nodes is present if they are close according to a function of the metric, a HGG generalizes a random geometric graph (RGG) whose embedding space is Euclidean. == Mathematical formulation == Mathematically, a HGG is a graph with a vertex set ''V'' (cardinality ) and a edge set ''E'' constructed by considering the nodes as points placed onto a 2-dimensional hyperbolic space of constant negative Gaussian curvature, and cut-off radius , i.e. the radius of the Poincaré disk which can be visualized using a hyperboloid model. Each point has hyperbolic polar coordinates with and . The hyperbolic law of cosines allows to measure the distance between two points and ,〔 : The angle is the (smallest) angle between the two position vectors. In the simplest case, an edge is established iff (if and only if) two nodes are within a certain ''neighborhood radius'' , , this corresponds to an influence threshold. 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「Hyperbolic geometric graph」の詳細全文を読む スポンサード リンク
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