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Related papers: Equivalences for weak crossed products

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This paper provides conditions (i) to distinguish weak supercyclicity form supercyclicity for operators acting on normed and Banach spaces, and also (ii) to ensure when weak supercyclicity implies weak stability.

Functional Analysis · Mathematics 2021-01-26 C. S. Kubrusly , B. P. Duggal

Given a C*-dynamical system (A,G,\alpha), we say that A is a weakly proper (X\rtimes G)-algebra if there exists a proper G-space X together with a nondegenerate G-equivariant *-homomorphism \phi:C_0(X)->M(A). Weakly proper G-algebras form a…

Operator Algebras · Mathematics 2014-06-02 Alcides Buss , Siegfried Echterhoff

In this second article on crossed products by "actions" of Hecke pairs we study their different C*-completions, namely we show how reduced and full C*-crossed products can be defined. We also establish that our construction coincides with…

Operator Algebras · Mathematics 2013-01-16 Rui Palma

The main objective consists in generalizing a well-known It{\^o} formula of J. Jacod and A. Shiryaev: given a c{\`a}dl{\`a}g process S, there is an equivalence between the fact that S is a semimartingale with given characteristics (B^k , C,…

Probability · Mathematics 2024-07-25 Elena Bandini , Francesco Russo

In this note we extend duality theorems for crossed products obtained by M. Koppinen and C. Chen from the case of a base field or a Dedekind domain to the case of an arbitrary noetherian commutative ground ring under fairly weak conditions.…

Rings and Algebras · Mathematics 2007-05-23 Jawad Y. Abuhlail

We introduce the notion of a matched pair of fusion rings and fusion categories, generalizing the one for groups. Using this concept, we define the bicrossed product of fusion rings and fusion categories and we construct exact…

Quantum Algebra · Mathematics 2025-07-09 Monique Müller , Héctor Martín Peña Pollastri , Julia Plavnik

Let k be a number field. For a variety X over k that satisfies weak approximation with Brauer-Manin obstruction, we study the same property for smooth projective models of its symmetric products. Based on the same method, we also explore…

Algebraic Geometry · Mathematics 2023-06-01 Sheng Chen , Ziyang Zhang

We introduce the dynamic comparison property for minimal dynamical systems which has applications to the study of crossed product C*-algebras. We demonstrate that this property holds for a large class of systems which includes all examples…

Dynamical Systems · Mathematics 2013-07-01 Julian Buck

We explore classifiability of crossed products of actions of countable amenable groups on compact, metrizable spaces. It is completely understood when such crossed products are simple, separable, unital, nuclear and satisfy the UCT: these…

Operator Algebras · Mathematics 2024-05-08 Eusebio Gardella , Shirly Geffen , Rafaela Gesing , Grigoris Kopsacheilis , Petr Naryshkin

A survey is given of results about coherence for categories with finite products and coproducts. For these results, which were published previously by the authors in several places, some formulations and proofs are here corrected, and…

Category Theory · Mathematics 2008-12-08 K. Dosen , Z. Petric

In this paper, we point out that the definition of weak tracial approximation can be improved and strengthened. An example of weak tracial approximation is also provided.

Operator Algebras · Mathematics 2022-09-27 Xiaochun Fang , Junqi Yang

Orderability, weak orderability and the existence of continuous weak selections on filter spaces (i.e., spaces with a single non-isolated point) and their products are discussed. We prove that a closed continuous image X of a suborderable…

General Topology · Mathematics 2017-10-19 Koichi Motooka , Dmitri Shakhmatov , Takamitsu Yamauchi

This paper studies weakly mixing (singular) and mixing masas in type $\rm{II}_{1}$ factors from a bimodule point of view. Several necessary and sufficient conditions to characterize the normalizing algebra of a masa are presented. We also…

Operator Algebras · Mathematics 2017-01-02 Jan Cameron , Junsheng Fang , Kunal Mukherjee

We characterize the hypocompact radical of a semicrossed product in terms of properties of the dynamical system. We show that an element A of a semicrossed product is in the hypocompact radical if and only if the Fourier coefficients of A…

Operator Algebras · Mathematics 2022-10-13 G. Andreolas , M. Anoussis , C. Magiatis

We establish common fixed point theorems for two pairs of weakly compatible self-mappings using an auxiliary function of two variables. Unlike classical results, our theorems do not assume continuity of the mappings and require completeness…

Functional Analysis · Mathematics 2025-08-13 Babu G. V. R. , Alemayehu Negash , Meaza Bogale

We propose a definition of double categories whose composition of 1-cells is weak in both directions. Namely, a doubly weak double category is a double computad -- a structure with 2-cells of all possible double-categorical shapes --…

Category Theory · Mathematics 2026-05-25 Aaron David Fairbanks , Michael Shulman

We study the weakest convergence-type conditions for fixed point results for Banach and Kannan mappings. Building on Suzuki's weakest condition for Banach mappings and our previous result for Kannan mappings, we compare convergence…

Functional Analysis · Mathematics 2026-05-13 Shunya Hashimoto , Misako Kikkawa , Shuji Machihara , Aqib Saghir

We derive an analytic approximation for the concurrence of weakly mixed bipartite quantum states - typical objects in state of the art experiments. This approximation is shown to be a lower bound of the concurrence of arbitrary states.

Quantum Physics · Physics 2009-11-10 Florian Mintert , Andreas Buchleitner

We establish an equivalence between two forms of the composition condition for the Abel differential equation with trigonometric coefficients.

Dynamical Systems · Mathematics 2013-07-24 F. Pakovich

Weak bisimilarity is a distribution-based equivalence notion for Markov automata. It has gained some popularity as the coarsest reasonable behavioural equivalence on Markov automata. This paper studies a strictly coarser notion: Late weak…

Formal Languages and Automata Theory · Computer Science 2014-01-15 Christian Eisentraut , Jens Chr. Godskesen , Holger Hermanns , Lei Song , Lijun Zhang