Operators associated with the Jacobi semigroup

Pseudodifferential operators associated with a semigroup of operators

new semigroup compactifications via the enveloping semigroups of associated flows

this thesis deals with the construction of some function algebras whose corresponding semigroup compactification are universal with respect to some properies of their enveloping semigroups. the special properties are of beigan a left zero, a left simple, a group, an inflation of the right zero, and an inflation of the rectangular band.

Intersection graphs associated with semigroup acts

The intersection graph $mathbb{Int}(A)$ of an $S$-act $A$ over a semigroup $S$ is an undirected simple graph whose vertices are non-trivial subacts of $A$, and two distinct vertices are adjacent if and only if they have a non-empty intersection. In this paper, we study some graph-theoretic properties of $mathbb{Int}(A)$ in connection to some algebraic properties of $A$. It is proved that the fi...

Submajorization inequalities associated with $tau$-measurable operators

The aim of this note is to study the submajorization inequalities for $tau$-measurable operators in a semi-finite von Neumann algebra on a Hilbert space with a normal faithful semi-finite trace $tau$. The submajorization inequalities generalize some results due to Zhang, Furuichi and Lin, etc..

Pseudo-riemannian Manifolds with Commuting Jacobi Operators

We study the geometry of pseudo-Riemannian manifolds which are Jacobi–Tsankov, i.e. J (x)J (y) = J (y)J (x) for all x, y. We also study manifolds which are 2-step Jacobi nilpotent, i.e. J (x)J (y) = 0 for all x, y.