>[!tldr] Page rank >The page rank is a [[Probability distribution|probability distribution]] over the vertices of the [[Webgraph]] $G = (V,E)$. This is a function $\pi : V \rightarrow [0,1]$ that assigns a ranking to each page. It is defined recursively as > $\pi(x) = \sum_{y \in In(x)} \frac{\pi(y)}{\vert Out(y) \vert}.$ > With > - $Out(x) = \{y \in V \vert (x,y) \in E\}$, and > - $In(x) = \{y \in V \vert (y,x) \in E\}$.