Mathematica Bohemica, Vol. 145, No. 2, pp. 113-126, 2020
A note on preservation of spectra for two given operators
Carlos Carpintero, Alexander Gutiérrez, Ennis Rosas, José Sanabria
Received March 24, 2018. Published online March 6, 2019.
Abstract: We study the relationships between the spectra derived from Fredholm theory corresponding to two given bounded linear operators acting on the same space. The main goal of this paper is to obtain sufficient conditions for which the spectra derived from Fredholm theory and other parts of the spectra corresponding to two given operators are preserved. As an application of our results, we give conditions for which the above mentioned spectra corresponding to two multiplication operators acting on the space of functions of bounded $p$-variation in Wiener's sense coincide. Additional illustrative results are given too.
Keywords: restriction of an operator; spectral property; semi-Fredholm spectra; multiplication operator
Affiliations: Carlos Carpintero, Universidad de Oriente, Av. Gran Mariscal-Edif. Rectorado, Cumaná, Venezuela and Universidad Autónoma del Caribe, Calle 90 # 46-112, Barranquilla, Atlántico, Colombia, e-mail: carpintero.carlos@gmail.com; Alexander Gutiérrez, Universidad Autónoma del Caribe, Calle 90 # 46-112, Barranquilla, Atlántico, Colombia, e-mail: algutierrez10@gmail.com; Ennis Rosas, Departamento de Matemáticas, Universidad de Oriente, Av. Gran Mariscal-Edif. Rectorado, Cumaná, Venezuela and Departamento de Ciencias Naturales y Exactas, Universidad de la Costa, Calle 58 # 55-66, Barranquilla, Colombia, e-mail: ennisrafael@gmail.com, erosas@cuc.edu.co; José Sanabria, Departamento de Matemáticas, Universidad de Oriente, Av. Gran Mariscal-Edif. Rectorado, Cumaná and Venezuela and Facultad de Ciencias Básicas, Universidad del Atlántico, Carrera 43 # 50-53, Barranquilla, Colombia, e-mail: jesanabri@gmail.com