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This paper is concerned with emptyness of the essential spectrum, or equivalently compactness of the semigroup, for perturbations of selfadjoint operators that are bounded below (on an L^2-space). For perturbations by a (nonnegative)…

Spectral Theory · Mathematics 2010-03-24 Daniel Lenz , Peter Stollmann , Daniel Wingert

We apply a method developed by one of the authors, see \cite{Arl1}, to localize the numerical range of \textit{quasi-sectorial} contractions semigroups. Our main theorem establishes a relation between the numerical range of quasi-sectorial…

Functional Analysis · Mathematics 2008-10-20 Yury Arlinskii , Valentin Zagrebnov

We introduce a special class of real semiflows, which is used to define a general type of evolution semigroups, associated to not necessarily exponentially bounded evolution families. Giving spectral characterizations of the corresponding…

Classical Analysis and ODEs · Mathematics 2023-03-29 Nicolae Lupa , Liviu Horia Popescu

In this paper we consider shift operators, self-adjoint, unitary and normal operators on the standard module over a unital C*-algebra A. We define various generalized spectra in A of these operators, give description of such spectra of…

Operator Algebras · Mathematics 2020-07-13 Stefan Ivkovic

In this paper, the spectrum, residual spectrum, point spectrum and spectral radius of weighted conditional type operators are computed. As an application, we give an equivalent condition for weighted conditional type operators to be…

Functional Analysis · Mathematics 2013-10-09 Yousef Estaremi

In this paper we introduce the concept of corner element of a generalized numerical semigroup, which extends in a sense the idea of conductor of a numerical semigroup to generalized numerical semigroups in higher dimensions. We present…

Group Theory · Mathematics 2022-01-19 Matheus Bernardini , Wanderson Tenório , Guilherme Tizziotti

We propose giving the mathematical concept of the pseudospectrum a central role in quantum mechanics with non-Hermitian operators. We relate pseudospectral properties to quasi-Hermiticity, similarity to self-adjoint operators, and basis…

Spectral Theory · Mathematics 2015-11-30 D. Krejcirik , P. Siegl , M. Tater , J. Viola

Fractional calculus and q-deformed Lie algebras are closely related. Both concepts expand the scope of standard Lie algebras to describe generalized symmetries. A new class of fractional q-deformed Lie algebras is proposed, which for the…

General Physics · Physics 2014-11-21 Richard Herrmann

We reveal new aspects of the structure of Hilbert space $C_0$-semigroups $\mathcal T = (T(t))_{t\ge 0}$ similar to semigroups of contractions. In particular, we prove that $\mathcal T$ is similar to a semigroup of contractions if and only…

Functional Analysis · Mathematics 2025-09-04 J. Oliva-Maza , Y. Tomilov

This paper determines almost symmetric numerical semigroups with maximal reduced type completely. In addition, this paper classifies MED-semigroups with maximal reduced type.

Commutative Algebra · Mathematics 2025-12-23 Akihiro Sugawara

We consider exponential ultradistribution semigroups with non--densely defined generators and give structural theorems for ultradistribution semigroups. Also structural theorems for exponential ultradistribution semigroups are given.

Functional Analysis · Mathematics 2013-06-06 Marko Kostić , Stevan Pilipović , Daniel Velinov

We introduce the quasi-ordinarization transform of a numerical semigroup. This transform will allow to organize all the semigroups of a given genus in a forest rooted at all quasi-ordinary semigroups with the given genus. This construction…

Combinatorics · Mathematics 2021-06-16 Maria Bras-Amorós , Hebert Pérez-Rosés , José Miguel Serradilla-Merinero

We explore the quark properties at finite temperature near but above the critical temperature of the chiral phase transition. We investigate the effects of the precursory soft mode of the phase transition on the quark dispersion relation…

High Energy Physics - Phenomenology · Physics 2009-11-11 Masakiyo Kitazawa , Teiji Kunihiro , Yukio Nemoto

In this paper we develop the definition of a global orthogonal spectrum and its unitary version. It relates $G-$equivariant spectra by equivariant weak equivalence in a coherent way. This category of global spectra has a model structure…

Algebraic Topology · Mathematics 2018-12-04 Zhen Huan

The new quantum number \sigma is introduced. It is shown that the conservation of \sigma-number results in the conservation of difference between baryon and lepton numbers obtained earlier by Georgi and Glashow. The conservation of \sigma…

High Energy Physics - Phenomenology · Physics 2007-05-23 N. A. Korkhmazyan , N. N. Korkhmazyan

In this paper the Jessen's type inequality for normalized positive $C_0$-semigroups is obtained. An adjoint of Jessen's type inequality has also been derived for the corresponding adjoint-semigroup, which does not give the analogous results…

Functional Analysis · Mathematics 2015-04-08 Gul I hina Aslam , Matloob Anwar

In this paper we characterize when a Cayley automaton semigroup is a group, is trivial, is finite, is free, is a left zero semigroup, or is a right zero semigroup.

Group Theory · Mathematics 2008-08-19 Victor Maltcev

In this paper we develop the basic homotopy theory of G-symmetric spectra (that is, symmetric spectra with a G-action) for a finite group G, as a model for equivariant stable homotopy with respect to a G-set universe. This model lies in…

Algebraic Topology · Mathematics 2018-05-07 Markus Hausmann

Expository notes about spectral sequences, filtered spectra, and synthetic spectra. We focus on the $\tau$-formalism as it arises in filtered spectra.

Algebraic Topology · Mathematics 2025-12-24 Sven van Nigtevecht

We study the spectra of non-regular semisimple elements in irreducible representations of simple algebraic groups. More precisely, we prove that if G is a simply connected simple linear algebraic group and f is a non-trivial irreducible…

Representation Theory · Mathematics 2021-06-11 Donna M Testerman , Alexandre Zalesski