@article{Rabanovych_2005, title={On the Decomposition of a Diagonal Operator into a Linear Combination of Idempotents or Projectors}, volume={57}, url={https://umj.imath.kiev.ua/index.php/umj/article/view/3606}, abstractNote={For a bounded operator that is not a sum of scalar and compact operators and is similar to a diagonal operator, we prove that it is a linear combination of three idempotents. It is also proved that any self-adjoint diagonal operator is a linear combination of four orthoprojectors with real coefficients.}, number={3}, journal={Ukrains’kyi Matematychnyi Zhurnal}, author={Rabanovych, V. I.}, year={2005}, month={Mar.}, pages={388–393} }