Institution: | Department of Mathematics, General Education, Tsuruoka National College of Technology, Tsuruoka, 997--8511, Japan ; Department of Mathematics, Shaanxi Normal University, Xian, 710062, Shaanxi, People's Republic of China ; Department of Mathematics, Faculty of Science, Niigata University, Niigata, 950--21, Japan |
Abstract: | Let be a covariant system and let be a covariant representation of on a Hilbert space . In this note, we investigate the representation of the covariance algebra and the -weakly closed subalgebra generated by and in the case of or when there exists a pure, full, -invariant subspace of . |