English

Drunk Angel and Hiding Devil

Combinatorics 2024-01-04 v2

Abstract

The angel game is played on 22-dimensional infinite grid by 22 players, the angel and the devil. In each turn, the angel of power cNc \in \mathbb{N} moves from her current point (x,y)(x, y) to a point (x,y)(x', y') which max{xx,yy}c\max\{|x - x'|, |y - y'|\} \leq c while the devil chooses a point to destroy in his turn. Then, the angel can no longer land on these destroyed points. The angel wins if she has a strategy to escape from the devil forever and the devil wins if he can cage the angel in his destroyed points by a finite number of turns. It was proved in 2007 that the angel of power at least 22 always wins. In this paper, we rise the problem when the angel is drunk. She randomly moves to any point in the range of her power in each turn. In our game version, the devil must cage the angel by a given finite number of turns, otherwise, the angel wins. We present a strategy for the devil that: if the devil plays with this strategy, then for given cNc \in \mathbb{N} and ϵ>0\epsilon > 0, the devil can cage the angel of power cc with probability greater than 1ϵ1 - \epsilon if and only if the game is played on an nn-dimensional infinite grid when n2n \leq 2. We also establish the results related to the hitting time once the angel is first time outside an nn-dimensional sphere of a given radius. The numerical simulation results are also presented in the last section.

Cite

@article{arxiv.2202.08988,
  title  = {Drunk Angel and Hiding Devil},
  author = {Nuttanon Songsuwan and Anuwat Tangthanawatsakul and Pawaton Kaemawichanurat},
  journal= {arXiv preprint arXiv:2202.08988},
  year   = {2024}
}

Comments

20 pages, 5 figure sets, 2 tables

R2 v1 2026-06-24T09:43:43.101Z