Reachable returns a list of all vertices reachable from the vertex v in the graph G.

A vertex w is said to be reachable from a vertex v if there exists a path in the graph from v to w.

To produce an actual spanning tree of vertices reachable from v, see SpanningTree or MinimalSpanningTree.

$\mathrm{with}\left(\mathrm{GraphTheory}\right)\:$

$\mathrm{C6}≔\mathrm{CycleGraph}\left(6\right)$

$\mathrm{C6}≔\mathrm{Graph\; 1:\; an\; undirected\; unweighted\; graph\; with\; 6\; vertices\; and\; 6\; edge(s)}$

$\mathrm{Reachable}\left(\mathrm{C6}\,1\right)$

$\left[1\,2\,3\,4\,5\,6\right]$

$G≔\mathrm{Graph}\left(5\,\left\{\left[1\,2\right]\,\left[2\,3\right]\,\left\{1\,4\right\}\,\left\{4\,5\right\}\right\}\right)$

$G≔\mathrm{Graph\; 2:\; a\; directed\; unweighted\; graph\; with\; 5\; vertices\; and\; 6\; arc(s)}$

$\mathrm{Reachable}\left(G\,2\right)$

$\left[2\,3\right]$

The GraphTheory[Reachable] command was introduced in Maple 2018.

For more information on Maple 2018 changes, see Updates in Maple 2018.