Media type: E-Article Title: Degenerate self-adjoint perturbation in Hilbert space Contributor: Nambu, Takao imprint: Project Euclid, 1987 Published in: Proceedings of the Japan Academy, Series A, Mathematical Sciences Language: Not determined DOI: 10.3792/pjaa.63.379 ISSN: 0386-2194 Keywords: General Mathematics Origination: Footnote: Access State: Open Access