ABSTRACT
In this note, for any two orthogonal projections P,Q on a Hilbert space, the characterization of spectrum of anticommutator PQ+QP has been obtained. As a corollary, an alternative proof of the norm formula
has been obtained (see Walters S. Anticommutator norm formula for projection operators, arXiv:1604.00699vl [math.FA] 3 Apr 2016).
2010 MATHEMATICS SUBJECT CLASSIFICATION:
Acknowledgements
The authors thank the referees for their valuable comments and suggestions.
Disclosure statement
No potential conflict of interest was reported by the authors.