Displaying similar documents to “Characterizations of partial isometries and two special kinds of EP elements”

Range of a contractive strongly positive projection in a C*-algebra

Andrzej Łuczak (2015)

Colloquium Mathematicae

Similarity:

We generalize a result of Choi and Effros on the range of a contractive completely positive projection in a C*-algebra to the case when this projection is only strongly positive using, moreover, an elementary argument instead of a 2×2-matrix technique.

Rings in which elements are the sum of a nilpotent and a root of a fixed polynomial that commute

Ali H. Handam, Hani A. Khashan (2017)

Open Mathematics

Similarity:

An element in a ring R with identity is said to be strongly nil clean if it is the sum of an idempotent and a nilpotent that commute, R is said to be strongly nil clean if every element of R is strongly nil clean. Let C(R) be the center of a ring R and g(x) be a fixed polynomial in C(R)[x]. Then R is said to be strongly g(x)-nil clean if every element in R is a sum of a nilpotent and a root of g(x) that commute. In this paper, we give some relations between strongly nil clean rings and...

σ-ring and σ-algebra of Sets1

Noboru Endou, Kazuhisa Nakasho, Yasunari Shidama (2015)

Formalized Mathematics

Similarity:

In this article, semiring and semialgebra of sets are formalized so as to construct a measure of a given set in the next step. Although a semiring of sets has already been formalized in [13], that is, strictly speaking, a definition of a quasi semiring of sets suggested in the last few decades [15]. We adopt a classical definition of a semiring of sets here to avoid such a confusion. Ring of sets and algebra of sets have been formalized as non empty preboolean set [23] and field of subsets...

Absolutely strongly star-Hurewicz spaces

Yan-Kui Song (2015)

Open Mathematics

Similarity:

A space X is absolutely strongly star-Hurewicz if for each sequence (Un :n ∈ℕ/ of open covers of X and each dense subset D of X, there exists a sequence (Fn :n ∈ℕ/ of finite subsets of D such that for each x ∈X, x ∈St(Fn; Un) for all but finitely many n. In this paper, we investigate the relationships between absolutely strongly star-Hurewicz spaces and related spaces, and also study topological properties of absolutely strongly star-Hurewicz spaces.