Bulletin of the Iranian Mathematical Society

Bulletin of the Iranian Mathematical Society

The reverse order law for Moore-Penrose inverses of operators on Hilbert C*-modules

Document Type : Research Paper

Authors
1 Department of Mathematics, Shahrood University of Technology, and, Mathematisches Institut, Fachbereich Mathematik und Informatik der Universitat Munster, Einsteinstrasse 62, 48149 Munster, Germany.
2 Department of‎ ‎Mathematics‎, ‎International Campus of Ferdowsi University‎, ‎Mashhad‎, ‎Iran.
Abstract
Suppose $T$ and $S$ are Moore-Penrose invertible operators between
Hilbert C*-module. Some necessary and sufficient conditions are given for the
reverse order law $(TS)^{ dag} =S^{ dag} T^{ dag}$ to hold.
In particular, we show that the equality holds if and only if $Ran(T^{*}TS) subseteq Ran(S)$ and $Ran(SS^{*}T^{*}) subseteq Ran(T^{*}),$ which was studied first by Greville [{it SIAM Rev. 8 (1966) 518--521}] for matrices.
Keywords
Subjects

Volume 42, Issue 1 - Serial Number 1
February 2016
Pages 53-60

  • Receive Date 16 August 2012
  • Revise Date 26 October 2014
  • Accept Date 26 October 2014