Rolle’s Theorem and Negligibility of Points in Infinite Dimensional Banach Spaces

In this note we prove that if a differentiable function oscillates between y« and « on the boundary of the unit ball then there exists a point in the interior of the ball in which the differential of the function has norm equal or less than« . This kind of approximate Rolle’s theorem is interesting...

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Detalles Bibliográficos
Autores: Azagra Rueda, Daniel, Gómez Gil, Javier, Jaramillo Aguado, Jesús Ángel
Tipo de recurso: artículo
Fecha de publicación:1997
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/57128
Acceso en línea:https://hdl.handle.net/20.500.14352/57128
Access Level:acceso abierto
Palabra clave:517.98
Rolle’s theorem in infinite-dimensional Banach spaces
Approximate Rolle’s theorem
Continuous norm whose dual norm is locally uniformly rotund
C1 bump function
Análisis funcional y teoría de operadores
Descripción
Sumario:In this note we prove that if a differentiable function oscillates between y« and « on the boundary of the unit ball then there exists a point in the interior of the ball in which the differential of the function has norm equal or less than« . This kind of approximate Rolle’s theorem is interesting because an exact Rolle’s theorem does not hold in many infinite dimensional Banach spaces. A characterization of those spaces in which Rolle’s theorem does not hold is given within a large class of Banach spaces. This question is closely related to the existence of C1 diffeomorphisms between a Banach space X and X _ _04 which are the identity out of a ball, and we prove that such diffeomorphisms exist for every C1 smooth Banach space which can be linearly injected into a Banach space whose dual norm is locally uniformly rotund (LUR).