Characterizations of zero-diagonal operators (i.e., operators that have a diagonal whose entries consist entirely of zeros) and the norm-closure of these operators are obtained. Also included are new characterizations of trace class operators, self-commutators of bounded operators, and others. 0. Introduction. In [3], it is shown that a hermitian compact operator is a self-commutator of a compa...

We examine k-minimal and k-maximal operator spaces and operator systems, and investigate their relationships with the basic separability problem in quantum information theory. We show that the matrix norms that define the k-minimal operator spaces are equal to a family of norms that have been studied independently as a tool for detecting k-positive linear maps and bound entanglement. Similarly,...

Index theory has had profound impact on many branches of mathematics. In this note we discuss the context for a new kind of index theorem. We begin, however, with some operator-theoretic results. In [11] Berger and Shaw established that finitely cyclic hyponormal operators have trace-class self-commutators. In [9], [31] Berger and Voiculescu extended this result to operators whose self-commutat...

We discuss a proposal for the construction of lattice QCD with gauge action, fermionic action, θ–term, and the operators all based on the lattice Dirac operator D with exact chiral symmetry. The simplest regularization of this type uses the proposition that the classical limit of scalar gauge density associated with trace of D is (up to an additive constant) proportional to trF2, while the corr...

Interruption is a useful feature in programming and specification languages. Therefore, process algebras has been extended with an additional interrupt operator. We invent a class of event structures, called interrupt event structures, to give a true concurrent semantic to process algebras containing interruption. Interrupt event structures are more expressive than other event structures with r...

By utilizing different scalar equalities obtained via Hermite's interpolating polynomial, we will obtain lower and upper bounds for the difference in Ando's inequality and in the Edmundson-Lah-Ribariv c inequality for solidarities that hold for a class of $n$-convex functions. As an application, main results are applied to some operator means and relative operator entropy.

where dx is the Haar measure of G and C?(G) is the set of all (complexvalued) functions on G which are everywhere indefinitely differentia t e and which vanish outside a compact set. V is called the Gârding subspace of § . Let R and C be the fields of real and complex numbers respectively and g0 the Lie algebra of G. We complexify g0 to Q and denote by $8 the universal enveloping algebra of Q [...

GivenS|R a finite Galois extension of finite chain rings andB anS-linear code we define twoGalois operators, the closure operator and the interior operator. We proof that a linear code is Galois invariant if and only if the row standard form of its generator matrix has all entries in the fixed ring by the Galois group and show a Galois correspondence in the class of S-linear codes. As applicati...