On the Whitham hierarchy: dressing scheme, string equations and additional symmetries

A new description of the universal Whitham hierarchy in terms of a factorization problem in the Lie group of canonical transformations is provided. This scheme allows us to give a natural description of dressing transformations, string equations and additional symmetries for the Whitham hierarchy. W...

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Detalles Bibliográficos
Autores: Mañas Baena, Manuel Enrique, Medina, Elena, Martínez Alonso, Luis
Tipo de recurso: artículo
Fecha de publicación:2006
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/51533
Acceso en línea:https://hdl.handle.net/20.500.14352/51533
Access Level:acceso abierto
Palabra clave:51-73
Dispersionless Kp hierarchy
Toda hierarchy
Integrable hierarchies
Tau-function
Hodograph solutions
Benney equations
Conformal-maps
Reductions
Growth
Limit
Física-Modelos matemáticos
Física matemática
Descripción
Sumario:A new description of the universal Whitham hierarchy in terms of a factorization problem in the Lie group of canonical transformations is provided. This scheme allows us to give a natural description of dressing transformations, string equations and additional symmetries for the Whitham hierarchy. We show how to dress any given solution and prove that any solution of the hierarchy may be undressed, and therefore comes from a factorization of a canonical transformation. A particularly important function, related to the tau-function, appears as a potential of the hierarchy. We introduce a class of string equations which extends and contains previous classes of string equations considered by Krichever and by Takasaki and Takebe. The scheme is also applied for a convenient derivation of additional symmetries. Moreover, new functional symmetries of the Zakharov extension of the Bentley gas equations are given and the action of additional symmetries over the potential in terms of linear PDEs is characterized.