Total-positivity conjecture for the reversed Stirling subset triangle

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Let \genfrac\{\}{\}{0pt}{}{n}{k} denote the Stirling subset number, and define the reversed Stirling subset triangle by \genfrac\{\}{\}{0pt}{}{n}{k}^{\rm rev}=\genfrac\{\}{\}{0pt}{}{n}{n-k}. Write \bm{S}^{\rm rev}=\left(\genfrac\{\}{\}{0pt}{}{n}{k}^{\rm rev}\right)_{n,k\geq 0}. Total-positivity conjecture. The reversed Stirling subset triangle Srev\bm{S}^{\rm rev} is totally positive. The source emphasizes that total positivity need not be preserved by reversal and presents this assertion as an open conjecture; it later notes that the more general conjecture would imply it by specialization.

References

Primary source

Xi Chen, Bishal Deb, Alexander Dyachenko, Tomack Gilmore and Alan D. Sokal, “Coefficientwise total positivity of some matrices defined by linear recurrences”, arXiv:2012.03629 (2020).

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