Ray in a graph
= Ray in a graph
{title2=$(v_0,v_1,\ldots)$}
= Graph ray
{synonym}
A <graph ray> is an infinite <sequence> $v_0,v_1,\ldots$ of distinct <graph vertices> with an <edge> between consecutive <graph vertices>. Every infinite connected <locally finite graph> contains a <graph ray> from each <graph vertex>, by the <König infinity lemma> applied to its finite self-avoiding <graph paths>. An open <graph ray> witnesses an infinite <percolation cluster>.