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A new method for the construction of Fock-adapted operator Markovian cocycles is outlined, and its use is illustrated by application to a number of examples arising in physics and probability. The construction uses the Trotter-Kato Theorem…

Functional Analysis · Mathematics 2007-05-23 J. Martin Lindsay , Stephen J. Wills

If $a$ is a densely defined sectorial form in a Hilbert space which is possibly not closable, then we associate in a natural way a holomorphic semigroup generator with $a$. This allows us to remove in several theorems of semigroup theory…

Analysis of PDEs · Mathematics 2010-05-07 W. Arendt , A. F. M. ter Elst

In solid state systems, group representation theory is powerful in characterizing the behavior of quasiparticles, notably the energy degeneracy. While conventional group theory is effective in answering yes-or-no questions related to…

Materials Science · Physics 2024-07-12 Jiayu Li , Ao Zhang , Yuntian Liu , Qihang Liu

We investigate the connection between left exact $\infty$-functors between finitely complete quasicategories and exact functors between fibration categories, describing a procedure to approximate flat $\infty$-functors of the former type by…

Category Theory · Mathematics 2026-02-20 El Mehdi Cherradi

We show that for every quasivariety K of structures (where both functions and relations are allowed) there is a semilattice S with operators such that the lattice of quasi-equational theories of K (the dual of the lattice of…

Rings and Algebras · Mathematics 2012-12-06 Kira Adaricheva , J. B. Nation

In [8](arXiv:2111.06159) we introduced the notion of a k-almost-quasifibration. In this article we update this definition and call it a k-c-quasifibration. This will help us to relate it to quasifibrations. We study some basic properties of…

Algebraic Topology · Mathematics 2022-08-16 S. K. Roushon

We give a functional characterization of a class of quasi-invariant determinantal processes corresponding to projection kernels in terms of de Branges spaces of entire funcitons.

Functional Analysis · Mathematics 2024-10-08 Roman Romanov

We briefly review a recently developed semiclassical theory for quantum oscillations in the spatial (particle and kinetic energy) densities of finite fermion systems and present some examples of its results. We then discuss the inclusion of…

Mathematical Physics · Physics 2015-05-14 Matthias Brack , Jerôme Roccia

A quasi-automatic semigroup is defined by a finite set of generators, a rational (regular) set of representatives, such that if a is a generator or neutral, then the graph of right multiplication by a on the set of representatives is a…

Group Theory · Mathematics 2019-06-12 Benjamin Blanchette , Christian Choffrut , Christophe Reutenauer

We give a detailed survey of the theory of quasidiagonal C*-algebras. The main structural results are presented and various functorial questions around quasidiagonality are discussed. In particular we look at what is currently known (and…

Operator Algebras · Mathematics 2007-05-23 Nathanial P. Brown

Functorial semi-norms are semi-normed refinements of functors such as singular (co)homology. We investigate how different types of representability affect the (non-)triviality of finite functorial semi-norms on certain functors or classes.…

Algebraic Topology · Mathematics 2015-09-08 Clara Loeh

Perturbation theory, the quasiclassical approximation and the quantum surface of section method are combined for the first time. This solves the long standing problem of quantizing the resonances and chaotic regions generically appearing in…

chao-dyn · Physics 2009-10-31 R. E. Prange , R. Narevich , Oleg Zaitsev

In this paper, we introduce the notion of Reidemeister torsion for quasi-isomorphisms of based chain complexes over a field. We call a chain map a quasi-isomorphism if its induced homomorphism between homology is an isomorphism. Our notion…

Algebraic Topology · Mathematics 2007-05-23 Jae-Wook Chung , Xiao-Song Lin

This paper advances a line of research in fixed point theory initiated by M. Bessenyei and Z. P\'ales, building on their introduction of the triangle function concept in [J. Nonlinear Convex Anal, Vol 18 (3), 515-524 (2017)]. By applying…

General Topology · Mathematics 2025-01-03 Ravindra K. Bisht , Evgen O. Petrov

Families of quasi-permutable normal operators in octonion Hilbert spaces are investigated. Their spectra are studied. Multiparameter semigroups of such operators are considered. A non-associative analog of Stone's theorem is proved.

Functional Analysis · Mathematics 2018-12-18 S. V. Ludkovsky

We introduce quasi-Prufer extensions of rings in order to relativize the notion of quasi-Prufer domains and to take into account some contexts recently introduced in the literature. We also introduce almost-Prufer ring extensions.…

Commutative Algebra · Mathematics 2016-11-01 Gabriel Picavet , Martine Picavet-L'Hermitte

The extension of Hille-Phillips functional calculus of semigroup generators which leads to unbounded operators is given. Connections of this calculus to Bochner-Phillips functional calculus are indicated, and several examples are…

Functional Analysis · Mathematics 2019-12-18 A. R. Mirotin

This note records some dilation theorems about contraction semigroups on a Hilbert space - all of which fall into the categories "known" or "probably known" - that I proved while working on my PhD in mathematics (under the supervision of…

Functional Analysis · Mathematics 2010-04-07 Orr Shalit

Let R be a commutative Noetherian domain, and let M and N be finitely generated R-modules. We give new criteria for determining when M tensor N has torsion. We also give constructive formulas for producing a module in the isomorphism class…

Commutative Algebra · Mathematics 2012-11-14 Micah Josiah Leamer

We ascertain conditions and structures on categories and semigroups which admit the construction of pseudo-products and trace products respectively, making their connection as precise as possible. This topic is modelled on the ESN Theorem…

Rings and Algebras · Mathematics 2022-10-14 D. G. FitzGerald , M. K. Kinyon