Acta mathematica scientia,Series A ›› 2009, Vol. 29 ›› Issue (6): 1477-1486.

• Articles • Previous Articles     Next Articles

Invertibility of Differences of Two Generalized |Idempotent Operators

  

  1. School of Mathematics Science, South China Normal University, Guangzhou 510631
  • Received:2007-12-08 Revised:2008-10-06 Online:2009-12-25 Published:2009-12-25
  • Supported by:

    国家自然科学基金(10571113)资助

Abstract:

Let P and Q be two idempotents on a Hilbert space H. The  set ω(P) of generalized idempotent operators with respect to P is defined by ω(P)={AB(H): A2=α A+β P, AP=PA=AP2=P, for some α, β ∈C}. In this note, the author proves that the invertibility of A-B is completely determined by the invertibility of  P-Q,  and R(AB) is closed if and only if  R(PQ) is closed for arbitrary A ∈ω(P) and B ∈ω(Q) such that A2=α A + β P, B2=mB+nQ, where β n ≠ 0, α and m are arbitrary.

Key words: Idempotent, Invertibility, Operator matrix

CLC Number: 

  • 47A05
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