Displaying similar documents to “On operator bands”

Sturdy bands of semigroups.

Miroslav Ciric, Stojan Bogdanovic (1990)

Collectanea Mathematica

Similarity:

In this paper we consider band compositions determined by two transitive systems of monomorphisms, called the sturdy bands of semigroups.

An irreducible semigroup of idempotents

Roman Drnovšek (1997)

Studia Mathematica

Similarity:

We construct a semigroup of bounded idempotents with no nontrivial invariant closed subspace. This answers a question which was open for some time.

Elements of C*-algebras commuting with their Moore-Penrose inverse

J. Koliha (2000)

Studia Mathematica

Similarity:

We give new necessary and sufficient conditions for an element of a C*-algebra to commute with its Moore-Penrose inverse. We then study conditions which ensure that this property is preserved under multiplication. As a special case of our results we recover a recent theorem of Hartwig and Katz on EP matrices.