Percolation cluster
= Percolation cluster
{title2=$C(x)$}
In <bond percolation>, a <percolation cluster> is a <connected component of a graph> formed by the open <edges>, with every <graph vertex> retained. In <site percolation>, it is a <connected component of a graph> of the subgraph induced by the open <graph vertices>. Write $C(x)$ for the cluster containing $x$; for <site percolation> set $C(x)=\varnothing$ when $x$ is closed.