The truth is always more boring:
"Here, we deal with a problem of guaranteed search on graphs ?with a radius of capture?...the main features of the guaranteed search in general can be studied from the article (Breisch, 1967) by speleologist Richard Breisch. Breisch considered the following problem. A person is lost in a cave, which is in total darkness, and wandering aimlessly. We are looking for an efficient way for rescue party to search the lost person: what is the minimum number of searchers required to explore a cave so that it is impossible to miss finding the victim if he is in the cave. ...
Now, let the cave be represented by the finite connected graph G so that the rooms are described by vertices and the passages ? by edges. We may assume that G is embedded in IR3 so that its vertices are points in IR3 and its edges are represented by closed line segments which intersect only at vertices of G. The searchers must proceed according to a predetermined plan which will find the lost man even if he was that sort of victim who knows the searcher?s every move, is arbitrarily fast and invisible for rescuers, and tries to avoid meeting "
from:
Graph Searching Games with a Radius of Capture ⋆ Tatiana V. Abramovskaya and Nikolai N. Petrov, presented at the Fourth International Conference Game Theory and Management June 28-30, 2010, St. Petersburg, Russia
It can be very hard for mathematicians trying to make their book stand out from all the other books on the subject ...