International Journal of Mathematics and Mathematical Sciences
Volume 10 (1987), Issue 3, Pages 621-623
doi:10.1155/S0161171287000760
M-quasi-hyponormal composition operators
Pushpa R. Suri
and N. Singh
Department of Mathematics, Kurukshetra University, Kurukshetra 132 119, India
Abstract
A necessary and sufficient condition is obtained for M-quasi-hyponormal composition operators. It has also been proved that the class of M-quasi-hyponormal composition operators coincides with the class of M-paranormal composition operators. Existence of M-hyponormal composition operators which are not hyponormal; and M-quasihyponormal composition operators which are not M-hyponormal and quasi-hyponormal are also shown.