A companion of Ostrowski's inequality for complex functions defined on the unit circle and applications
Gang�Li, Yue�Luan, Jiangyong�Yu*
ABSTRACT: Some companions of Ostrowski's inequality for complex functions defined on the unit circle are proved. Our results in special cases not only recapture known results, but also give a smaller estimator than that of the known results. Applications to a composite quadrature rule and to functions of unitary operators in Hilbert spaces are also considered.