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→Density
The density <math>D</math> of a network is defined as a ratio of the number of edges <math>E</math> to the number of possible edges in a network with <math>N</math> nodes, given (in the case of simple graphs) by the [[binomial coefficient]] <math>\tbinom N2</math>, giving <math>D =\frac{E-(N-1)}{Emax - (N-1)} = \frac{2(E-N+1)}{N(N-3)+2}</math>
The density <math>D</math> of a network is defined as a ratio of the number of edges <math>E</math> to the number of possible edges in a network with <math>N</math> nodes, given (in the case of simple graphs) by the [[binomial coefficient]] <math>\tbinom N2</math>, giving <math>D =\frac{E-(N-1)}{Emax - (N-1)} = \frac{2(E-N+1)}{N(N-3)+2}</math>
Another possible equation is <math>D = \frac{T-2N+2}{N(N-3)+2},</math> whereas the ties <math>T</math> are unidirectional (Wasserman & Faust 1994).<ref>http://psycnet.apa.org/journals/prs/9/4/172/</ref> This gives a better overview over the network density, because unidirectional relationships can be measured.
Another possible equation is <math>D = \frac{T-2N+2}{N(N-3)+2},</math> whereas the ties <math>T</math> are unidirectional (Wasserman & Faust 1994).<ref>http://psycnet.apa.org/journals/prs/9/4/172/</ref> This gives a better overview over the network density, because unidirectional relationships can be measured.
=== 密度 Density ===
网络的密度 <math>D</math> 通常定义为连边数量<math>E</math>和节点数量<math>N</math> 的比值，给定二分系数binomial coefficient（如简单图中） <math>\tbinom N2</math>，假定<math>D =\frac{E-(N-1)}{Emax - (N-1)} = \frac{2(E-N+1)}{N(N-3)+2}</math>，另外一个可能的等式就是<math>D = \frac{T-2N+2}{N(N-3)+2}</math> ，而<math>T</math> 节是没有方向的(Wasserman & Faust 1994)。这为网络密度提供了更好的概述，因为可以度量单向关系。
=== Planar Network Density ===
=== Planar Network Density ===