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6 votes
1 answer
361 views

Random walks on infinite directed regular graphs

Let us consider a directed graph $\Gamma=(V,E,s,t)$ ($V$ set of vertices, $E$ set of edges, $s,t: E \rightarrow V$ are the "source" and "target" maps). Assume that $\Gamma$ is bi-regular, that is ...
Joël's user avatar
  • 26k
4 votes
2 answers
261 views

Probability question about random shuffling of piles of rocks

I have $k$ piles of rocks placed on a circle so that every pile has exactly two neighboring piles. We know that initially the piles have $x_1,\dots,x_k$ rocks in each respectively. A monkey plays the ...
David's user avatar
  • 41
3 votes
0 answers
115 views

Approximating the *conditional* probability of 1D discrete random walk not having revisited the origin given last position

I'm looking for a good closed form approximation to the following conditional probability, with provable approximation guarantees. Consider a 1D random walk on the integers, starting at the origin, ...
user113925's user avatar
0 votes
1 answer
414 views

Exact formula for computing n-step transition probability of random walks with self-transitions

Consider a semi-infinite random walks $X_n$, $n=0,1,2,\ldots$, whose state space is a set of consecutive integers and whose one-step transition probabilities are $P_{ij}=\mathrm{Pr}\{X_{n+1}=j|X_n=i\}$...
yeliqseu's user avatar
1 vote
1 answer
92 views

Choose uniformly from fixed-length paths in $[0,n]\cap\mathbb{Z}$ with fixed start and end

Let $X_k$ be a symmetric (discrete time) random walk on $\mathbb{Z}$ and let $m,n\in\mathbb{N}$. I want to chose uniformly from the paths of $X_k$, which start at $0$ stay in $[0,n]\cap\mathbb{Z}$ ...
Ikaros's user avatar
  • 113
1 vote
0 answers
46 views

Is there an effective algorithm for finding "minimal discovery times" for large graphs?

Consider a large, probably sparse graph with Markovian random walkers on it. Define the discovery time as the expected time to first reach a vertex by random walk from a uniform start. Are there ...
Moonwalker's user avatar