Sokal's total monomial positivity conjecture for Hadamard products of dual Jacobi–Trudi matrices

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Let x=(x1,x2,)\mathbf{x}=(x_1,x_2,\dots) and y=(y1,y2,)\mathbf{y}=(y_1,y_2,\dots) be distinct sequences of variables, and let

M(x)=(eji(x))i,j0,M(\mathbf{x})=\bigl(e_{j-i}(\mathbf{x})\bigr)_{i,j\geq 0},

where eke_k denotes the elementary symmetric function. For skew shapes λ/μ\lambda/\mu, define the dual Jacobi–Trudi matrix

Eλ/μ(x)=(eλiμji+j(x))i,j=1(λ).\mathcal{E}_{\lambda/\mu}(\mathbf{x})=\bigl(e_{\lambda_i-\mu_j-i+j}(\mathbf{x})\bigr)_{i,j=1}^{\ell(\lambda)}.

Sokal's conjecture. The Hadamard product M(x)M(y)M(\mathbf{x})*M(\mathbf{y}) is totally monomial positive; equivalently, every minor

det(Eλ/μ(x)Eλ/μ(y))\det\bigl(\mathcal{E}_{\lambda/\mu}(\mathbf{x})*\mathcal{E}_{\lambda/\mu}(\mathbf{y})\bigr)

is a multi-symmetric function in x\mathbf{x} and y\mathbf{y} with nonnegative integer coefficients. This strengthens Maló's total-positivity theorem by asking for coefficientwise positivity rather than positivity after specializing the variables to nonnegative real numbers. The source does not state whether the conjecture has been resolved.

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Sources & referencesView supporting material

Primary source

Robert Angarone, Jang Soo Kim, Jaeseong Oh and Daniel Soskin, “Hadamard Products of dual Jacobi-Trudi matrices”, arXiv:2511.08969 (2025).

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