English

The product of operators with closed range in Hilbert C*-modules

Operator Algebras 2011-02-25 v3

Abstract

Suppose TT and SS are bounded adjointable operators with close range between Hilbert C*-modules, then TSTS has closed range if and only if Ker(T)+Ran(S)Ker(T)+Ran(S) is an orthogonal summand, if and only if Ker(S)+Ran(T)Ker(S^*)+Ran(T^*) is an orthogonal summand. Moreover, if the Dixmier (or minimal) angle between Ran(S)Ran(S) and Ker(T)[Ker(T)Ran(S)]Ker(T) \cap [Ker(T) \cap Ran(S)]^{\perp} is positive and Ker(S)+Ran(T)ˉ \bar{Ker(S^*)+Ran(T^*)} is an orthogonal summand then TSTS has closed range.

Keywords

Cite

@article{arxiv.1010.4574,
  title  = {The product of operators with closed range in Hilbert C*-modules},
  author = {Kamran Sharifi},
  journal= {arXiv preprint arXiv:1010.4574},
  year   = {2011}
}

Comments

12 pages, abstract was changed, accepted

R2 v1 2026-06-21T16:32:28.801Z