Inverse Sequences and Absolute Co-Extensors

Ivan Ivanšić; Leonard R. Rubin

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Displaying similar documents to “Inverse Sequences and Absolute Co-Extensors”

Invertibility of the commutator of an element in a C*-algebra and its Moore-Penrose inverse

Julio Benítez, Vladimir Rakočević (2010)

Studia Mathematica

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We study the subset in a unital C*-algebra composed of elements a such that $a a^{†} - a a^{†}$ is invertible, where $a^{†}$ denotes the Moore-Penrose inverse of a. A distinguished subset of this set is also investigated. Furthermore we study sequences of elements belonging to the aforementioned subsets.

On the classification of inverse limits of tent maps

Louis Block, Slagjana Jakimovik, Lois Kailhofer, James Keesling (2005)

Fundamenta Mathematicae

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Let $f_{s}$ and $f_{t}$ be tent maps on the unit interval. In this paper we give a new proof of the fact that if the critical points of $f_{s}$ and $f_{t}$ are periodic and the inverse limit spaces $(I, f_{s})$ and $(I, f_{t})$ are homeomorphic, then s = t. This theorem was first proved by Kailhofer. The new proof in this paper simplifies the proof of Kailhofer. Using the techniques of the paper we are also able to identify certain isotopies between homeomorphisms on the inverse limit space.

The inverse problem in the calculus of variations: new developments

Thoan Do, Geoff Prince (2021)

Communications in Mathematics

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We deal with the problem of determining the existence and uniqueness of Lagrangians for systems of $n$ second order ordinary differential equations. A number of recent theorems are presented, using exterior differential systems theory (EDS). In particular, we indicate how to generalise Jesse Douglas’s famous solution for $n = 2$ . We then examine a new class of solutions in arbitrary dimension $n$ and give some non-trivial examples in dimension 3.

Some properties of the topology of $α$ -sets

D. Andrijević (1984)

Matematički Vesnik

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Weighted $w$ -core inverses in rings

Liyun Wu, Huihui Zhu (2023)

Czechoslovak Mathematical Journal

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Let $R$ be a unital $*$ -ring. For any $a, s, t, v, w \in R$ we define the weighted $w$ -core inverse and the weighted dual $s$ -core inverse, extending the $w$ -core inverse and the dual $s$ -core inverse, respectively. An element $a \in R$ has a weighted $w$ -core inverse with the weight $v$ if there exists some $x \in R$ such that $a w x v x = x$ , $x v a w a = a$ and ${(a w x)}^{*} = a w x$ . Dually, an element $a \in R$ has a weighted dual $s$ -core inverse with the weight $t$ if there exists some $y \in R$ such that $y t y s a = y$ , $a s a t y = a$ and ${(y s a)}^{*} = y s a$ . Several characterizations of weighted $w$ -core invertible and weighted dual $s$ -core...

Characterization of the convolution operators on quasianalytic classes of Beurling type that admit a continuous linear right inverse

José Bonet, Reinhold Meise (2008)

Studia Mathematica

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Extending previous work by Meise and Vogt, we characterize those convolution operators, defined on the space $_{(ω)} (ℝ)$ of (ω)-quasianalytic functions of Beurling type of one variable, which admit a continuous linear right inverse. Also, we characterize those (ω)-ultradifferential operators which admit a continuous linear right inverse on $_{(ω)} [a, b]$ for each compact interval [a,b] and we show that this property is in fact weaker than the existence of a continuous linear right inverse on $_{(ω)} (ℝ)$ .

Inverse topology in MV-algebras

Fereshteh Forouzesh, Farhad Sajadian, Mahta Bedrood (2019)

Mathematica Bohemica

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We introduce the inverse topology on the set of all minimal prime ideals of an MV-algebra $A$ and show that the set of all minimal prime ideals of $A$ , namely $Min (A)$ , with the inverse topology is a compact space, Hausdorff, $T_{0}$ -space and $T_{1}$ -space. Furthermore, we prove that the spectral topology on $Min (A)$ is a zero-dimensional Hausdorff topology and show that the spectral topology on $Min (A)$ is finer than the inverse topology on $Min (A)$ . Finally, by open sets of the inverse topology, we define and study a congruence...

A remark on a lower envelope principle

Masanori Kishi (1964)

Annales de l'institut Fourier

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Soit $Ω$ un espace topologique localement séparé et soit $G$ un noyau (symétrique ou non) positif et continu au sens large dans $Ω$ . Si $G$ satisfait au principe de domination ordinaire et si le noyau adjoint $\overset{ˇ}{G}$ est régulier, alors $X$ satisfait au principe de l’enveloppe inférieure sur tout compact, c’est-à-dire, pour tout compact $K \subset Ω$ et toutes mesures positives $μ$ et $ν$ (l’une d’elles d’énergie finie), il existe une mesure positive $λ$ portée par $K$ telle que $G λ = G μ \land G ν$ à p.p.p. sur $K$ . Ici nous considérons le...

A classification of inverse limit spaces of tent maps with periodic critical points

Lois Kailhofer (2003)

Fundamenta Mathematicae

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We work within the one-parameter family of symmetric tent maps, where the slope is the parameter. Given two such tent maps $f_{a}$ , $f_{b}$ with periodic critical points, we show that the inverse limit spaces $(_{a}, f_{a})$ and $(_{b}, g_{b})$ are not homeomorphic when a ≠ b. To obtain our result, we define topological substructures of a composant, called “wrapping points” and “gaps”, and identify properties of these substructures preserved under a homeomorphism.

The only continuous Volterra right inverses in $C_{c} [0, 1]$ of the operator $d / d t$ are $ʃ_{a}^{t}$

D. Przeworska-Rolewicz, S. Rolewicz (1987)

Colloquium Mathematicae

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The Ascoli property for function spaces and the weak topology of Banach and Fréchet spaces

S. Gabriyelyan, J. Kąkol, G. Plebanek (2016)

Studia Mathematica

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Following Banakh and Gabriyelyan (2016) we say that a Tychonoff space X is an Ascoli space if every compact subset of $C_{k} (X)$ is evenly continuous; this notion is closely related to the classical Ascoli theorem. Every $k_{ℝ}$ -space, hence any k-space, is Ascoli. Let X be a metrizable space. We prove that the space $C_{k} (X)$ is Ascoli iff $C_{k} (X)$ is a $k_{ℝ}$ -space iff X is locally compact. Moreover, $C_{k} (X)$ endowed with the weak topology is Ascoli iff X is countable and discrete. Using some basic concepts from probability...

Linearization of isometric embedding on Banach spaces

Yu Zhou, Zihou Zhang, Chunyan Liu (2015)

Studia Mathematica

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Let X,Y be Banach spaces, f: X → Y be an isometry with f(0) = 0, and $T : \bar{s p a n} (f (X)) \to X$ be the Figiel operator with $T \circ f = I d_{X}$ and ||T|| = 1. We present a sufficient and necessary condition for the Figiel operator T to admit a linear isometric right inverse. We also prove that such a right inverse exists when $\bar{s p a n} (f (X))$ is weakly nearly strictly convex.

On locally $S$ -closed spaces

Takashi Noiri (1983)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

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Si studiano le condizioni sotto cui l’immagine (o l'immagine inversa) di uno spazio localmente $S$ -chiuso sia localmente $S$ -chiuso.

Complexity of the method of averaging

Dalík, Josef

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The general method of averaging for the superapproximation of an arbitrary partial derivative of a smooth function in a vertex $a$ of a simplicial triangulation $𝒯$ of a bounded polytopic domain in $ℜ^{d}$ for any $d \geq 2$ is described and its complexity is analysed.

A hit-and-miss topology for $2^{X}$ , Cₙ(X) and Fₙ(X)

Benjamín Espinoza, Verónica Martínez-de-la-Vega, Jorge M. Martínez-Montejano (2009)

Colloquium Mathematicae

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A hit-and-miss topology ( $τ_{H M}$ ) is defined for the hyperspaces $2^{X}$ , Cₙ(X) and Fₙ(X) of a continuum X. We study the relationship between $τ_{H M}$ and the Vietoris topology and we find conditions on X for which these topologies are equivalent.

Absolute continuity with respect to a subset of an interval

Lucie Loukotová (2017)

Commentationes Mathematicae Universitatis Carolinae

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The aim of this paper is to introduce a generalization of the classical absolute continuity to a relative case, with respect to a subset $M$ of an interval $I$ . This generalization is based on adding more requirements to disjoint systems ${(a_{k}, b_{k})}_{K}$ from the classical definition of absolute continuity – these systems should be not too far from $M$ and should be small relative to some covers of $M$ . We discuss basic properties of relative absolutely continuous functions and compare this class with other...

Extension properties of Stone-Čech coronas and proper absolute extensors

A. Chigogidze (2013)

Fundamenta Mathematicae

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We characterize, in terms of X, the extensional dimension of the Stone-Čech corona βX∖X of a locally compact and Lindelöf space X. The non-Lindelöf case is also settled in terms of extending proper maps with values in $I^{τ} ∖ L$ , where L is a finite complex. Further, for a finite complex L, an uncountable cardinal τ and a $Z_{τ}$ -set X in the Tikhonov cube $I^{τ}$ we find a necessary and sufficient condition, in terms of $I^{τ} ∖ X$ , for X to be in the class AE([L]). We also introduce a concept of a proper absolute...