Someone explain low time in graphs

Can someone explain low time of a node?

@galencolin @aneee004

Also pls answer this

A depth-first search actually gives you a lot of information. It is not just limited to finding components and traversing a graph. By assigning an entry time and an exit time for each node, we get a lot of information about types of edges present in the graph (forward edge, back edge, or a bridge). Check out Page 5 here, there is a lot of information about lo time and hi time of a vertex.

Also, in trees you can easily tell if u is an ancestor of v just by checking if lo[u] < lo[v] < hi[v] < hi[u].

P.S: I assumed this is what you meant by low time of a node. Is that right?