International Journal of Mathematics and Mathematical Sciences 
Volume 7 (1984), Issue 1, Pages 205-207
doi:10.1155/S0161171284000223

An operator inequality

P. D. Siafarikas

Department of Mathematics, Section of Applied Mathematics, University of Patra, Patra, Greece

Received 10 November 1983; Revised 1 December 1983

Abstract

An inequality is proved in abstract separable Hilbert space H where A and B are bounded self-adjoint positive operators defined in H such that R(A)=R(B) and R(A) is closed.