Ordinal pattern probabilities for symmetric random walks

An ordinal pattern for a finite sequence of real numbers is a permutation that records the relative positions in the sequence. For random walks with steps drawn uniformly from $[-1,1]$, we show an ordinal pattern occurs with probability $\frac{\mathrm{\mid }[1,w]\mathrm{\mid }}{2^{n}n!}$, where $[1,w]$ is a weak order interval in the affine Weyl group ${\tilde{A}}_n$. For random walks with steps drawn from a symmetric Laplace distribution, the probability is $\frac{1}{2^n \prod_{j=1}^n $\mathrm{l}\mathrm{e}\mathrm{v}$(\pi)_j}$,where$$\mathrm{l}\mathrm{e}\mathrm{v}$(\pi)_j$ measures how often $j$ occurs between consecutive values in $\pi$. Permutations whose consecutive values are at most two positions apart in $\pi$ are shown to occur with the same probability for any choice of symmetric continuous step distribution. For random walks with steps from a mean zero normal distribution, ordinal pattern probabilities are determined by a matrix whose $ij$-th entry measures how often $i$ and $j$ are between consecutive values.