Positivity Proofs for Linear Recurrences through Contracted Cones

Fuente: arXiv
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Main Authors: Ibrahim, Alaa, Salvy, Bruno
Format: Preprint
Published: 2024
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author Ibrahim, Alaa
Salvy, Bruno
author_facet Ibrahim, Alaa
Salvy, Bruno
contents Deciding the positivity of a sequence defined by a linear recurrence with polynomial coefficients and initial condition is difficult in general. Even in the case of recurrences with constant coefficients, it is known to be decidable only for order up to~5. We consider a large class of linear recurrences of arbitrary order, with polynomial coefficients, for which an algorithm decides positivity for initial conditions outside of a hyperplane. The underlying algorithm constructs a cone, contracted by the recurrence operator, that allows a proof of positivity by induction. The existence and construction of such cones relies on the extension of the classical Perron-Frobenius theory to matrices leaving a cone invariant.
format Preprint
id arxiv_https___arxiv_org_abs_2412_08576
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Positivity Proofs for Linear Recurrences through Contracted Cones
Ibrahim, Alaa
Salvy, Bruno
Symbolic Computation
Deciding the positivity of a sequence defined by a linear recurrence with polynomial coefficients and initial condition is difficult in general. Even in the case of recurrences with constant coefficients, it is known to be decidable only for order up to~5. We consider a large class of linear recurrences of arbitrary order, with polynomial coefficients, for which an algorithm decides positivity for initial conditions outside of a hyperplane. The underlying algorithm constructs a cone, contracted by the recurrence operator, that allows a proof of positivity by induction. The existence and construction of such cones relies on the extension of the classical Perron-Frobenius theory to matrices leaving a cone invariant.
title Positivity Proofs for Linear Recurrences through Contracted Cones
topic Symbolic Computation
url https://arxiv.org/abs/2412.08576