Ergodic theorems for random sets with density zero

1994 ◽  
Vol 14 (1) ◽  
pp. 141-149
Author(s):  
Yenkun Huang
Keyword(s):  
Positive Solution ◽  
Ergodic Theorem ◽  
The Other ◽  
Random Sets ◽  
Asymptotic Density ◽  
Necessary Condition ◽  
Ergodic Theorems ◽  
Mean Ergodic Theorem ◽  
Density Zero ◽  
Sufficient And Necessary Condition

AbstractWe generalize a result of Bourgain and a result of Huang. We also give a positive solution to A. Bellow's question: the a.e. convergence of the averages for σn = 1/n. On the other hand, we establish a sufficient and necessary condition for random sets in Z+ with asymptotic density zero which almost surely satisfy a mean ergodic theorem.

Random sets for the pointwise ergodic theorem

1992 ◽  
Vol 12 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Yenkun Huang
Keyword(s):  
Ergodic Theorem ◽  
The Other ◽  
Random Sets ◽  
Simple Condition ◽  
Random Set ◽  
Large Classes ◽  
Pointwise Ergodic Theorem ◽  
Other Hand ◽  
Density Zero ◽  
Banach Density

AbstractWe generalize a result of Bourgain and devise more general criteria which guarantee that the corresponding random set in Z+ almost surely satisfies a pointwise ergodic theorem on Lp for p > 1. Several large classes of examples are constructed. We also show that under a simple condition the corresponding random set in Z+ almost surely satisfies a pointwise ergodic theorem not only on Lp for p > 1 but also on L1. On the other hand, we establish a criterion to conclude that a certain class of random sets have Banach density zero. In particular, all of the examples mentioned have Banach density zero.

scholarly journals Approximation byq-Bernstein Polynomials in the Caseq→1+

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Xuezhi Wu
Keyword(s):  
Bernstein Polynomials ◽  
The Other ◽  
Necessary Condition ◽  
Standard Case ◽  
Other Hand ◽  
Approximating Sequence ◽  
Sufficient And Necessary Condition

LetBn,q(f;x),q∈(0,∞)be theq-Bernstein polynomials of a functionf∈C[0,1]. It has been known that, in general, the sequenceBn,qn(f)withqn→1+is not an approximating sequence forf∈C[0,1], in contrast to the standard caseqn→1-. In this paper, we give the sufficient and necessary condition under which the sequenceBn,qn(f)approximatesffor anyf∈C[0,1]in the caseqn>1. Based on this condition, we get that if1<qn<1+ln⁡2/nfor sufficiently largen, thenBn,qn(f)approximatesffor anyf∈C[0,1]. On the other hand, ifBn,qn(f)can approximateffor anyf∈C[0,1]in the caseqn>1, then the sequence(qn)satisfieslim¯n→∞n(qn-1)≤ln2.

A mean ergodic theorem of an amenable group action

2014 ◽  
Vol 17 (01) ◽  
pp. 1450003 ◽  
Author(s):  
Anilesh Mohari
Keyword(s):  
Ergodic Theorem ◽  
Group Action ◽  
Von Neumann Algebra ◽  
Amenable Group ◽  
Ergodic Theorems ◽  
Von Neumann ◽  
Mean Ergodic Theorem ◽  
Faithful Normal State ◽  
Contractive Maps ◽  
Dual Banach Space

We consider a sequence of weak Kadison–Schwarz maps τn on a von-Neumann algebra ℳ with a faithful normal state ϕ sub-invariant for each (τn, n ≥ 1) and use a duality argument to prove strong convergence of their pre-dual maps when their induced contractive maps (Tn, n ≥ 1) on the GNS space of (ℳ, ϕ) are strongly convergent. The result is applied to deduce improvements of some known ergodic theorems and Birkhoff's mean ergodic theorem for any locally compact second countable amenable group action on the pre-dual Banach space ℳ*.

scholarly journals Mean ergodic theorems on norming dual pairs

2013 ◽  
Vol 34 (4) ◽  
pp. 1210-1229 ◽  
Author(s):  
MORITZ GERLACH ◽  
MARKUS KUNZE
Keyword(s):  
Banach Space ◽  
Ergodic Theorem ◽  
Additional Assumption ◽  
Dual Pair ◽  
Ergodic Theorems ◽  
Dual Pairs ◽  
Space Setting ◽  
Mean Ergodic Theorem ◽  
Markovian Semigroups

AbstractWe extend the classical mean ergodic theorem to the setting of norming dual pairs. It turns out that, in general, not all equivalences from the Banach space setting remain valid in our situation. However, for Markovian semigroups on the norming dual pair $({C}_{b} (E), \mathscr{M} (E))$ all classical equivalences hold true under an additional assumption which is slightly weaker than the e-property.

scholarly journals On Arnol’d’s and Kazhdan’s equidistribution problems

2011 ◽  
Vol 32 (6) ◽  
pp. 1972-1990 ◽  
Author(s):  
ALEXANDER GORODNIK ◽  
AMOS NEVO
Keyword(s):  
Invariant Measure ◽  
Ergodic Theorem ◽  
Homogeneous Spaces ◽  
Duality Principle ◽  
Ergodic Theorems ◽  
Absolutely Continuous ◽  
Mean Ergodic Theorem ◽  
Isometric Actions ◽  
Dense Subgroups ◽  
Transitive Actions

AbstractWe consider isometric actions of lattices in semisimple algebraic groups on (possibly non-compact) homogeneous spaces with (possibly infinite) invariant Radon measure. We assume that the action has a dense orbit, and demonstrate two novel and non-classical dynamical phenomena that arise in this context. The first is the existence of a mean ergodic theorem even when the invariant measure is infinite; this implies the existence of an associated limiting distribution, which can be different from the underlying invariant measure. The second is uniform quantitative equidistribution of all orbits in the space, which follows from a quantitative mean ergodic theorem for such actions. In turn, these results imply quantitative ratio ergodic theorems for isometric actions of lattices. This sheds some unexpected light on certain equidistribution problems posed by Arnol’d [Arnol’d’s Problems. Springer, Berlin, 2004] and also on the ratio equidistribution conjecture for dense subgroups of isometries formulated by Kazhdan [Uniform distribution on a plane. Tr. Mosk. Mat. Obs. 14 (1965), 299–305]. We briefly mention the general problem regarding ergodic theorems for actions of lattices on homogeneous spaces and its solution given by Gorodnik and Nevo [Duality principle and ergodic theorems, in preparation], and present a number of examples to demonstrate our results. Finally, we also prove results on quantitative equidistribution for absolutely continuous averages in transitive actions.

Mean ergodic theorem in function symmetric spaces for infinite measure

2018 ◽  
Vol 2018 (1) ◽  
pp. 35-46
Author(s):  
Vladimir Chilin ◽  
◽  
Aleksandr Veksler ◽  
Keyword(s):  
Ergodic Theorem ◽  
Symmetric Spaces ◽  
Infinite Measure ◽  
Mean Ergodic Theorem

scholarly journals Cauchy matrix and Liouville formula of quaternion impulsive dynamic equations on time scales

2020 ◽  
Vol 18 (1) ◽  
pp. 353-377 ◽  
Author(s):  
Zhien Li ◽  
Chao Wang
Keyword(s):  
Time Scales ◽  
Quaternion Algebra ◽  
Matrix Exponential ◽  
Dynamic Equations ◽  
Necessary Condition ◽  
Quaternion Matrix ◽  
Exponential Functions ◽  
Cauchy Matrix ◽  
Adjoint Matrix ◽  
Sufficient And Necessary Condition

Abstract In this study, we obtain the scalar and matrix exponential functions through a series of quaternion-valued functions on time scales. A sufficient and necessary condition is established to guarantee that the induced matrix is real-valued for the complex adjoint matrix of a quaternion matrix. Moreover, the Cauchy matrices and Liouville formulas for the quaternion homogeneous and nonhomogeneous impulsive dynamic equations are given and proved. Based on it, the existence, uniqueness, and expressions of their solutions are also obtained, including their scalar and matrix forms. Since the quaternion algebra is noncommutative, many concepts and properties of the non-quaternion impulsive dynamic equations are ineffective, we provide several examples and counterexamples on various time scales to illustrate the effectiveness of our results.

scholarly journals Sufficient and necessary conditions for oscillation of linear fractional-order delay differential equations

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Qiong Meng ◽  
Zhen Jin ◽  
Guirong Liu
Keyword(s):  
Differential Equation ◽  
Fractional Order ◽  
Sufficient Conditions ◽  
Necessary Condition ◽  
Multiple Delays ◽  
All Solutions ◽  
Sufficient And Necessary Conditions ◽  
Delay Differential ◽  
T Tau ◽  
Sufficient And Necessary Condition

AbstractThis paper studies the linear fractional-order delay differential equation $$ {}^{C}D^{\alpha }_{-}x(t)-px(t-\tau )= 0, $$ D − α C x ( t ) − p x ( t − τ ) = 0 , where $0<\alpha =\frac{\text{odd integer}}{\text{odd integer}}<1$ 0 < α = odd integer odd integer < 1 , $p, \tau >0$ p , τ > 0 , ${}^{C}D_{-}^{\alpha }x(t)=-\Gamma ^{-1}(1-\alpha )\int _{t}^{\infty }(s-t)^{- \alpha }x'(s)\,ds$ D − α C x ( t ) = − Γ − 1 ( 1 − α ) ∫ t ∞ ( s − t ) − α x ′ ( s ) d s . We obtain the conclusion that $$ p^{1/\alpha } \tau >\alpha /e $$ p 1 / α τ > α / e is a sufficient and necessary condition of the oscillations for all solutions of Eq. (*). At the same time, some sufficient conditions are obtained for the oscillations of multiple delays linear fractional differential equation. Several examples are given to illustrate our theorems.

scholarly journals Research on the Relationship between Shared Leadership and Individual Creativity-Qualitative Comparative Analysis on the Basis of Clear Set

2021 ◽  
Vol 13 (10) ◽  
pp. 5445
Author(s):  
Muyun Sun ◽  
Jigan Wang ◽  
Ting Wen
Keyword(s):  
Comparative Analysis ◽  
Environmental Factors ◽  
Shared Leadership ◽  
Management Practices ◽  
Qualitative Comparative Analysis ◽  
Necessary Condition ◽  
The Individual ◽  
The Impact ◽  
The Relationship ◽  
Sufficient And Necessary Condition

Creativity is the key to obtaining and maintaining competitiveness of modern organizations, and it has attracted much attention from academic circles and management practices. Shared leadership is believed to effectively influence team output. However, research on the impact of individual creativity is still in its infancy. This study adopts the qualitative comparative analysis method, taking 1584 individuals as the research objects, underpinned by a questionnaire-based survey. It investigates the influence of the team’s shared leadership network elements and organizational environmental factors on the individual creativity. We have found that there are six combination of conditions of shared leadership and organizational environmental factors constituting sufficient combination of conditions to increase or decrease individual creativity. Moreover, we have noticed that the low network density of shared leadership is a sufficient and necessary condition of reducing individual creativity. Our results also provide management suggestions for practical activities during the team management.

scholarly journals A nonlocal game for witnessing quantum networks

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Ming-Xing Luo
Keyword(s):  
Computational Complexity ◽  
Main Idea ◽  
Bell Inequalities ◽  
Theoretical Computer Science ◽  
Graph Representation ◽  
Necessary Condition ◽  
Quantum Networks ◽  
Theoretical Computer ◽  
Sufficient And Necessary Condition ◽  
Unified Method

Abstract Nonlocal game as a witness of the nonlocality of entanglement is of fundamental importance in various fields. The well-known nonlocal games or equivalent linear Bell inequalities are only useful for Bell networks consisting of single entanglement. Our goal in this paper is to propose a unified method for constructing cooperating games in network scenarios. We propose an efficient method to construct multipartite nonlocal games from any graphs. The main idea is the graph representation of entanglement-based quantum networks. We further specify these graphic games with quantum advantages by providing a simple sufficient and necessary condition. The graphic games imply a linear Bell testing of the nonlocality of general quantum networks consisting of EPR states. It also allows generating new instances going beyond CHSH game. These results have interesting applications in quantum networks, Bell theory, computational complexity, and theoretical computer science.

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