On Parametric Linear System Solving

Fuente: arXiv
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Autori principali: Corless, Robert M., Giesbrecht, Mark, Sevyeri, Leili Rafiee, Saunders, B. David
Natura: Preprint
Pubblicazione: 2025
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author Corless, Robert M.
Giesbrecht, Mark
Sevyeri, Leili Rafiee
Saunders, B. David
author_facet Corless, Robert M.
Giesbrecht, Mark
Sevyeri, Leili Rafiee
Saunders, B. David
contents Parametric linear systems are linear systems of equations in which some symbolic parameters, that is, symbols that are not considered to be candidates for elimination or solution in the course of analyzing the problem, appear in the coefficients of the system. In this work we assume that the symbolic parameters appear polynomially in the coefficients and that the only variables to be solved for are those of the linear system. The consistency of the system and expression of the solutions may vary depending on the values of the parameters. It is well-known that it is possible to specify a covering set of regimes, each of which is a semi-algebraic condition on the parameters together with a solution description valid under that condition. We provide a method of solution that requires time polynomial in the matrix dimension and the degrees of the polynomials when there are up to three parameters. In previous methods the number of regimes needed is exponential in the system dimension and polynomial degree of the parameters. Our approach exploits the Hermite and Smith normal forms that may be computed when the system coefficient domain is mapped to the univariate polynomial domain over suitably constructed fields. Our approach effectively identifies intrinsic singularities and ramification points where the algebraic and geometric structure of the matrix changes.
format Preprint
id arxiv_https___arxiv_org_abs_2508_21629
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On Parametric Linear System Solving
Corless, Robert M.
Giesbrecht, Mark
Sevyeri, Leili Rafiee
Saunders, B. David
Rings and Algebras
Symbolic Computation
1502
Parametric linear systems are linear systems of equations in which some symbolic parameters, that is, symbols that are not considered to be candidates for elimination or solution in the course of analyzing the problem, appear in the coefficients of the system. In this work we assume that the symbolic parameters appear polynomially in the coefficients and that the only variables to be solved for are those of the linear system. The consistency of the system and expression of the solutions may vary depending on the values of the parameters. It is well-known that it is possible to specify a covering set of regimes, each of which is a semi-algebraic condition on the parameters together with a solution description valid under that condition. We provide a method of solution that requires time polynomial in the matrix dimension and the degrees of the polynomials when there are up to three parameters. In previous methods the number of regimes needed is exponential in the system dimension and polynomial degree of the parameters. Our approach exploits the Hermite and Smith normal forms that may be computed when the system coefficient domain is mapped to the univariate polynomial domain over suitably constructed fields. Our approach effectively identifies intrinsic singularities and ramification points where the algebraic and geometric structure of the matrix changes.
title On Parametric Linear System Solving
topic Rings and Algebras
Symbolic Computation
1502
url https://arxiv.org/abs/2508.21629