The interchange-process comparison inequality

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Let k≥2k\geq 2, let Sk\mathcal S_k be the symmetric group on kk letters, and let g:Sk→Rg:\mathcal S_k\to\mathbb R be any function. For nonnegative numbers γ1,…,γk−1\gamma_1,\ldots,\gamma_{k-1}, with an empty sum interpreted as zero and (ij)∈Sk(ij)\in\mathcal S_k denoting the transposition of ii and jj, the interchange-process comparison conjecture.

∑σ∈Sk∑i=1k−1γi[g(σ)−g((ik)σ)]2≥∑σ∈Sk∑1≤i<j≤k−1γiγjγ1+⋯+γk−1[g(σ)−g((ij)σ)]2.\sum_{\sigma\in\mathcal S_k}\sum_{i=1}^{k-1}\gamma_i\bigl[g(\sigma)-g((ik)\sigma)\bigr]^2\geq\sum_{\sigma\in\mathcal S_k}\sum_{1\leq i<j\leq k-1}\frac{\gamma_i\gamma_j}{\gamma_1+\cdots+\gamma_{k-1}}\bigl[g(\sigma)-g((ij)\sigma)\bigr]^2.

This inequality was proposed as a tool for controlling spectral changes in an induction argument for Aldous' conjecture, when a new vertex has degree k−1k-1. The supplied context describes it as a conjecture and says that the broader Aldous conjecture had been resolved, but gives no resolution status for this inequality itself.

References

Primary source

A. B. Dieker, “Interlacings for random walks on weighted graphs and the interchange process”, arXiv:0906.1716 (2009).

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