Bellman's lost in a forest problem
What is the optimal path to take when lost in a forest?
Bellman's lost-in-a-forest problem is an unsolved minimization problem in geometry, originating in 1955 by the American applied mathematician Richard E. Bellman.[1] The problem is often stated as follows: "A hiker is lost in a forest whose shape and dimensions are precisely known to him. What is the best path for him to follow to escape from the forest?"[2] It is usually assumed that the hiker does not know the starting point or direction he is facing. The best path is taken to be the one that minimizes the worst-case distance to travel before reaching the edge of the forest. Other variations of the problem have been studied.
Although real world applications are not apparent, the problem falls into a class of geometric optimization problems including search strategies that are of practical importance. A bigger motivation for study has been the connection to Moser's worm problem. It was included in a list of 12 problems described by the mathematician Scott W. Williams as "million buck problems" because he believed that the techniques involved in their resolution will be worth at least a million dollars to mathematics.[3]
Approaches[edit]
A proven solution is only known for a few shapes or classes of shape, such as a square and a circle. Others, such as an equilateral triangle, remain unknown.[4] A general solution would be in the form of a geometric algorithm which takes the shape of the forest as input and returns the optimal escape path as the output.
References[edit]
- ^ Bellman, R. (1956). "Minimization problem". Research problems. Bulletin of the American Mathematical Society. 62 (3): 270. doi:10.1090/S0002-9904-1956-10021-9.
- ^ Finch, S. R.; Wetzel, J. E. (2004). "Lost in a forest" (PDF). American Mathematical Monthly. 11 (8): 645–654. doi:10.2307/4145038. JSTOR 4145038. MR 2091541.
- ^ Williams, S. W. (2000). "Million buck problems" (PDF). National Association of Mathematicians Newsletter. 31 (2): 1–3.
- ^ Ward, John W. (2008). "Exploring the Bellman Forest Problem" (PDF). Retrieved 2020-12-14.