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Let $W_n$ be a self-avoiding random walk (SAW) on $\mathbb{Z}^2$, starting at the origin. Formally, $W_0=0$ and for $n\ge 0$, $W_{n+1}$ is chosen uniformly from the neighbours of $W_n$ which were not visited earlier: $$W_{n+1}\sim U\left(\{u\in\mathbb{Z}^2\mid u\sim W_n,\ \neg\exists0\le m<n:\ u=W_m\}\right)$$ (the inner $\sim$ sign means "neighbour of").

However, for a specific roll and for a specific $n$, it is possible that the set of unvisited neighbours from which $W_{n+1}$ should be chosen uniformly is empty. In that case, we say the walk is stuck, and leave it determined as is.

So my question is as follows:

  • what is the probability that such a random walk will be stuck?
  • if the probability is 1, what is the expectation of the hitting time of being stuck?
Bach
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