Neighbors returns a list of lists if the input is just a graph. The ith list is the list of neighbors of the ith vertex of the graph. Neighbors(G, v) returns the list of neighbors of vertex v in the graph G.

Arrivals returns a list of the lists of vertices which are at the tail of arcs directed into vertex i. Undirected edges are treated as if they were bidirectional. If a vertex v is specified, the output is only the list of vertices which are at the tail of arcs directed into vertex v.

Departures is similar to Arrivals, but returns a list of the lists of vertices which are at the head of edges directed out of vertex i. If a vertex v is specified, the output is only the list of vertices which are at the head of edge directed out of vertex v.