Past exam of the year 1 of the computer science course of the University of Oxford / 2017 / Functional programming, design and analysis of algorithms (resit) / 7 / c / ii / Solution

False. The same ordered traversal gives a path $u\to x\to v$, butA path from $u$ can pass through an already discovered ancestor, whose remaining edges are scanned only after $u$ finishes. A reachability statement alone therefore does not impose the claimed finishing-time bound.