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Sums and products of quasi-nilpotent operators

Published online by Cambridge University Press:  14 November 2011

C. K. Fong
Affiliation:
Department of Mathematics, University of Toronto, Toronto, Ontario M5S 1A1, Canada
A. R. Sourour
Affiliation:
Department of Mathematics, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada

Extract

It is proved that a bounded operator on Hilbert space is the sum of two quasi-nilpotent operators if and only if it is not a non-zero scalar plus a compact operator. Necessary conditions and sufficient conditions for an operator to be the product of two quasi-nilpotent operators are given.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1984

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References

1Anderson, H. H. and Stampfli, J. G.. Commuters and compressions. Israel J. Math. 10 (1971)., 433441.Google Scholar
2Brown, A and Pearcy, C.. Structure of commutators of operators. Ann. of Math. 82 (1965)., 112127.Google Scholar
3Brown, A, Pearcy, C. and Salinas, N.. Perturbations by nilpotent operators on Hilbert space. Proc. Amer. Math. Soc. 41 (1973)., 530534.Google Scholar
4Douglas, R. G.. On majorization, factorization, and range of inclusion of operators on Hilbert space. Proc. Amer. Math. Soc. 17 (1966)., 413415.Google Scholar
5Fillmore, P. A., Fong, C. K. and Scourour, A. R.. Real parts of quasi-nilpotent operators. Proc. Edinburgh Math. Soc. 22 (1979)., 263269.Google Scholar
6Fillmore, P. A., Stampfli, J. G. and Williams, J. P.. On the essential numerical range, the essential spectrum, and a problem of Halmos. Acta Sci. Math. (Szeged) 33 (1972)., 179192.Google Scholar
7Halmos, P. R.. A Hilbert Space Problem Book (New York: Van Nostrand, 1967).Google Scholar
8Pearcy, C. and Topping, D.. Sums of small numbers of idempotents. Michigan Math. J. 14 (1967)., 453465.Google Scholar
9Schatten, R.. Norm ideals of completely continuous operators (Berlin: Springer, 1960).Google Scholar
10Shoda, K.. Einige Sätze über Matrizen. Japan. J. Math. 13 (1936)., 361365.Google Scholar