arXiv · 2406.07104
Extensions of certain Markov inequalities to Toeplitz matrices
Abstract
We establish finite Toeplitz analogues of Markov's inequalities for Hankel determinants and zeros of orthogonal polynomials. We characterise the real symmetric positive-definite Toeplitz matrices whose determinants dominate those of all such matrices below them in the alternating moment order: non-negativity of the diagonal sums of deleted minors is necessary and sufficient. Equality holds only when the matrices coincide, and a quantitative estimate controls the determinant gap. Paraorthogonal zeros in the right half-plane provide a geometric sufficient condition in both parities. For differentiable finite Hermitian moment data, we derive individual and relative angular-velocity identities. For real symmetric data, these identities yield a finite comparison of all upper zeros under simultaneous changes in the moments: a semicircle condition at one endpoint is inherited by the other, and every angular inequality is strict when the matrices differ. No regularity assumption on a representing measure is required. Coefficient criteria also establish nearest-zero monotonicity. An exact Rogers-Szeg\H{o} counterexample shows that this need not extend to every upper zero.
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K. Castillo, A. Suzuki. 2024-06-11. Extensions of certain Markov inequalities to Toeplitz matrices. https://arxiv.org/abs/2406.07104
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