Normal operators in real and quaternionic Hilbert spaces
摘要
A new approach to normal operators in real Hilbert spaces isdiscussed, and a spectral representation is obtained, derived directly from thecomplex case. The results are then applied to quaternionic normal operators,regarded as a special class of real normal operators. This point of view allows usto consider their spectrum and associated measures to be defined on subsets ofthe complex plane, in a classical manner.