Burchnall–Chaundy polynomials for matrix ODOs and Picard–Vessiot theory

Burchnall and Chaundy showed that if two ordinary differential operators (ODOs) P, Q with analytic coefficients commute then there exists a polynomial f(λ, μ) with complex coefficients such that f(P, Q) = 0, called the BC-polynomial. This polynomial can be computed using the differential resultant f...

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Detalles Bibliográficos
Autores: Previato, Emma, Rueda, Sonia L., Zurro Moro, Ángeles
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:repositorio.uam.es:10486/708613
Acceso en línea:http://hdl.handle.net/10486/708613
https://dx.doi.org/10.1016/j.physd.2023.133811
Access Level:acceso abierto
Palabra clave:Differential Equations
Mathematical Operators
Polynomials
Matemáticas
Descripción
Sumario:Burchnall and Chaundy showed that if two ordinary differential operators (ODOs) P, Q with analytic coefficients commute then there exists a polynomial f(λ, μ) with complex coefficients such that f(P, Q) = 0, called the BC-polynomial. This polynomial can be computed using the differential resultant for ODOs. In this work we extend this result to matrix ordinary differential operators, MODOs. Our matrices have entries in a differential field K, whose field of constants C is algebraically closed and of zero characteristic. We restrict to the case of order one operators P, with invertible leading coefficient. We define a new differential elimination tool, the matrix differential resultant. We use it to compute the BC-polynomial f of a pair of commuting MODOs, and we also prove that it has constant coefficients. This resultant provides the necessary and sufficient condition for the spectral problem PY = λY, QY = μY to have a solution. Techniques from differential algebra and Picard–Vessiot theory allow us to describe explicitly isomorphisms between commutative rings of MODOs C[P, Q] and a finite product of rings of irreducible algebraic curves