bluuebunny/crossref_metadata_2025_split huggingface dataset:
The unsung impact of currency risk on the performance of international real property investment
Authors: Addae‐Dapaah Kwame , Tan Yong Hwee Wilfred 
Published: September 2008

AbstractThe paper revisits the currency risk debate to ascertain the statistical significance of currency risk on the return of international real property investment, especially in a period of increased exchange rate volatility. After statistical analyses of the returns of a portfolio of office investments in seven Asia Pacific cities over the 1986 to 2007 period, it was found that currency risk had a statistically significant positive impact on the performance of the portfolio of office investments. This is confirmed by the results of stochastic dominance test. If the results of this study are verified by subsequent studies, and the past reliably presages the future, they would imply that investors holding portfolios of real property investments in the sample markets might not need to be unduly concerned with currency risk.
Two millennia of glacier advances from southern Iceland dated by tephrochronology
Authors: Kirkbride Martin P. , Dugmore Andrew J. 
Published: September 2008

AbstractTwo glaciers at Eyjafjallajökull, south Iceland, provide a record of multiple episodes of glacier advance since the Sub-Atlantic period, ca. 2000 yr ago. A combination of tephrochronology and lichenometry was applied to date ice-marginal moraines, tills and meltwater deposits. Two glacier advances occurred before the 3rd century AD, others in the 9th and 12th centuries bracketing the Medieval Warm Period, and five groups of advances occurred between AD 1700 and 1930, within the Little Ice Age. The advances of Eyjafjallajökull before the Norse settlement (ca. AD 870) were synchronous with other glacier advances identified in Iceland. In contrast, medieval glacier advances between the 9th and 13th centuries are firmly identified for the first time in Iceland. This challenges the view of a prolonged Medieval Warm Period and supports fragmentary historical data that indicate significant medieval episodes of cooler and wetter conditions in Iceland. An extended and more detailed glacier chronology of the mid- and late Little Ice Age is established, which demonstrates that some small outlet glaciers achieved their Little Ice Age maxima around AD 1700. While Little Ice Age advances across Iceland appear to synchronous, the timing of the maximum differs between glacier type and region.
ON T DIRECTION OF ALGEBROID FUNCTION DEALING WITH MULTIPLE VALUES
Authors: WU ZHAOJUN , SUN DAOCHUN 
Published: September 2008

AbstractUsing Ahlfors’ theory of covering surfaces, we prove the existence theorem for the T direction for algebroid functions dealing with multiple values which extends the results proved by Guo, Zheng and Ng and answers a question by Wang, Giao and the present authors.
Bernoulli diffeomorphisms with n − 1 non-zero exponents
Authors: Brin M. 
Published: September 2008

AbstractFor every manifold of dimension n ≥ 5 a diffeomorphism f which has n − 1 non-zero characteristic exponents almost everywhere is constructed. The diffeomorphism preserves the Lebesgue measure and is Bernoulli with respect to this measure. To produce this example a diffeomorphism of the 2-disk is extended by means of an Anosov flow, and this skew product is embedded in ℝn.
Subadditive mean ergodic theorems
Authors: Derriennic Y. , Krengel U. 
Published: September 2008

AbstractThe authors investigate which results of the classical mean ergodic theory for bounded linear operators in Banach spaces have analogues for subadditive sequences (Fn) in a Banach lattice B. A sequence (Fn) is subadditive for a positive contraction T in B if Fn+k ≤ Fn + TnFk (n, k ≥ 1). For example, von Neumann's mean ergodic theorem fails to extend to the general subadditive case, but it extends to the non-negative subadditive case. It is shown that the existence of a weak cluster point f = Tf for (n−1Fn) implies In Lp (1 ≤ p < ∞) the existence of a weak cluster point for non-negative (n−1Fn) is equivalent with norm convergence. If T is an isometry in Lp (1 < p < ∞) and sup then n−1Fn converges weakly. If T in L1 has a strictly positive fixed point and sup then n−1Fn converges strongly. Most results are proved even in the d-parameter case.
Construction d'un difféomorphisme minimal d'entropie topologique non nulle
Authors: Herman M. R. 
Published: September 2008

AbstractWe construct a real analytic diffeomorphismFαon a compact connected 4-dimensional manifoldM, such thatFαpreserves a probability measure μ defined by a smooth volume form,Fαis a minimal diffeomorphism ofMand furthermore the metrical entropy ofFαwith respect to the measure μ is strictly positive. By a theorem of Goodwyn the topological entropy is also strictly positive. We write down the explicit formula ofFαthat depends on a parameter α ∈ T1. This parameter is chosen by Baire category.
An obstruction to the existence of certain dynamics in surface diffeomorphisms
Authors: Blanchard Paul , Franks John 
Published: September 2008

AbstractLet M be a two-dimensional, compact manifold and g:Μ→ΜM be a diffeomorphism with a hyperbolic chain recurrent set. We find restrictions on the reduced zeta function p(t) of anyzero-dimensional basic set of g. If deg (p(t)) is odd, then p(1) = 0 (in ). Since there are infinitely many subshifts of finite type whose reduced zeta functions do not satisfy these restrictions, there are infinitely many subshifts which cannot be basic sets for any diffeomorphism of any surface.
The infinite word problem and limit sets in Fuchsian groups
Authors: Series Caroline 
Published: September 2008

AbstractLet Г be a finitely generated non-elementary Fuchsian group acting in the disk. With the exception of a small number of co-compact Г, we give a representation of g ∈ Г as a product of a fixed set of generators Гo in a unique shortest ‘admissible form’. Words in this form satisfy rules which after a suitable coding are of finite type. The space of infinite sequences Σ of generators satisfying the same rules is identified in a natural way with the limit set Λ of Г by a map which is bijective except at a countable number of points where it is two to one. We use the theory of Gibbs measures onΣ to construct the so-called Patterson measure on Λ [8], [9]. This measure is, in fact, Hausdorff 5-dimensional measure on Λ, where S is the exponent of convergence of Г.
Capacity of attractors
Authors: Young Lai-Sang 
Published: September 2008

AbstractLet f be a diffeomorphism of a manifold and Λ be an f-invariant set supporting an ergodic Borel probability measure μ with certain properties. A lower bound on the capacity of Λ is given in terms of the μ-Lyapunov exponents. This applies in particular to Axiom A attractors and their Bowen-Ruelle measure.
On the entropy in II1 von Neumann algebras
Authors: Besson O. 
Published: September 2008

AbstractLet α be an automorphism of a finite von Neumann algebra and let H(α) be its Connes-Størmer's entropy. We show that H(α) = 0 if α is the induced automorphism on the crossed product of a Lebesgue space by a pure point spectrum transformation. We also show that H is not continuous in α and we compute H(α) for some α.
Symétrie et forme normale des centres et foyers dégénérés
Authors: Moussu Robert 
Published: September 2008

AbstractConsider an analytic differential equation ο = adx + bdy with an algebraically isolated singularity and without a separatrix. The germ at 0∈ℝ2 of the 1-jet y dy is either a focus or a centre. The equation has C∞ normal form of the type = with F(x) = F(−x) if and only if the germ is a centre.
Entropy estimates for geodesic flows
Authors: Sarnak P. 
Published: September 2008

AbstractLet M be a compact Riemannian manifold of (variable) negative curvature. Let h be the topological entropy and hμ the measure entropy for the geodesic flow on the unit tangent bundle to M. Estimates for h and hμ in terms of the ‘geometry’ of M are derived. Connections with and applications to other geometric questions are discussed.
Geometry of the Katok examples
Authors: Ziller Wolfgang 
Published: September 2008

AbstractWe consider examples of Finsler metrics symmetric or not) onSn,Pnℂ,Pnℍ, andP2Cawith only finitely many closed geodesies or with only few short closed geodesies. The number of closed geodesies in these examples and properties of the closed geodesies are considered.
On collective complete integrability according to the method of Thimm
Authors: Guillemin Victor , Sternberg Shlomo 
Published: September 2008

AbstractLet G be a Lie group acting in Hamiltonian fashion on a symplectic manifold M with moment map Φ:M → g*. A function of the form ƒ∘Φ where ƒ is a function on g* is called ‘collective’. We obtain necessary conditions on the G action for there to exist enough Poisson commuting functions on g* so that the corresponding collective functions on M form a completely integrable system. For the case G = O(n) or U(n) these conditions are sufficient. This explains Thimm's proof [17] of the complete integrability of the geodesic flow on the real and complex grassmanians. We also discuss related questions in the geometry of the moment map.
Real analytic actions of SL (2, ℝ) on a surface
Authors: Stowe Dennis C. 
Published: September 2008

AbstractReal analytic actions of connected Lie groups locally isomorphic to SL (2, ℝ) on compact surfaces, possibly with boundary, are classified up to topological conjugacy and up to real analytic conjugacy. Finite dimensional universal unfoldings of the real analytic conjugacy relation are also constructed. These are local transversals to the conjugacy classes in the space of actions. Sometimes the unfolding is a variety but not a manifold, and thus the space of actions is not naturally modelled on a vector space. We find many rigid actions and some unexpected bifurcation.
Stratification of the space of unimodal interval maps
Authors: Block Louis , Hart David 
Published: September 2008

AbstractThe space of ‘quadratic-like’ (unimodal) maps of a compact interval to itself is shown to decompose in a ‘nice’ way (stratify) according to a dynamical property of such maps (the existence of a homoclinic periodic orbit with given period). This decomposition is refined by that discovered by Sarkovskii. Orbit structure and bifurcation properties are also discussed.
Lower entropy factors of sofic systems
Authors: Boyle Mike 
Published: September 2008

AbstractA mixing subshift of finite type T is a factor of a sofic shift S of greater entropy if and only if the period of any periodic point of S is divisible by the period of some periodic point of T. Mixing sofic shifts T satisfying this theorem are characterized, as are those mixing sofic shifts for which Krieger's Embedding Theorem holds. These and other results rest on a general method for extending shift-commuting continuous maps into mixing subshifts of finite type.
Flows associated with product type odometers
Authors: Osikawa M. 
Published: September 2008

AbstractAn AC-flow is the associated flow of a product type odometer (PTO). We give examples of AC-flows and compute their L∞-point-spectra. We also introduce an invariant for isomorphism of aperiodic conservative ergodic nonsingular flows which is a closed subset of the unit interval and contains 0 and 1. We give a necessary condition for the associated flow of an approximately finite ergodic group to be finite measure preserving.
Twofold mixing implies threefold mixing for rank one transformations
Authors: Kalikow Steven Arthur 
Published: September 2008

AbstractThis paper addresses the following long-standing open question: If a stationary transformation on a probability space obeys the propertyfor all measurable sets A1, A2, does it follow thatfor all measurable sets A1, A2, A3? Here we answer the question affirmatively for a certain class of transformations.
On the notion of the dimension with respect to a dynamical system
Authors: Pesin Ya. B. 
Published: September 2008

AbstractFor the invariant sets of dynamical systems a new notion of dimension-the so-called dimension with respect to a dynamical system-is introduced. It has some common features with the general topological notion of the dimension, but it also reflects the dynamical properties of the system. In the one-dimensional case it coincides with the Hausdorff dimension. For multi-dimensional hyperbolic sets formulae for the calculation of our dimension are obtained. These results are generalizations of Manning's results obtained by him for the Hausdorff dimension in the two-dimensional case.
Approximation by Brownian motion for Gibbs measures and flows under a function
Authors: Denker Manfred , Philipp Walter 
Published: September 2008

AbstractLet denote a flow built under a Hölder-continuous function l over the base (Σ, μ) where Σ is a topological Markov chain and μ some (ψ-mining) Gibbs measure. For a certain class of functions f with finite 2 + δ-moments it is shown that there exists a Brownian motion B(t) with respect to μ and σ2 > 0 such that μ-a.e.for some 0 < λ < 5δ/588. One can also approximate in the same way by a Brownian motion B*(t) with respect to the probability . From this, the central limit theorem, the weak invariance principle, the law of the iterated logarithm and related probabilistic results follow immediately. In particular, the result of Ratner ([6]) is extended.
On the structure of the family of Cherry fields on the torus
Authors: Boyd Colin 
Published: September 2008

AbstractA class of vector fields on the 2-torus, which includes Cherry fields, is studied. Natural paths through this class are defined and it is shown that the parameters for which the vector field is unstable is the closure ofhas irrational rotation number}, where ƒ is a certain map of the circle andRtis rotation throught. This is shown to be a Cantor set of zero Hausdorff dimension. The Cherry fields are shown to form a family of codimension one submanifolds of the set of vector fields. The natural paths are shown to be stable paths.
Locally compact groups appearing as ranges of cocycles of ergodic ℤ-actions
Authors: Golodets V. Ya. , Sinelshchikov S. D. 
Published: September 2008

AbstractThe paper contains the proof of the fact that every solvable locally compact separable group is the range of a cocycle of an ergodic automorphism. The proof is based on the theory of representations of canonical anticommutation relations and the orbit theory of dynamical systems. The slight generalization of reasoning shows further that this result holds for amenable Lie groups as well and can be also extended to almost connected amenable locally compact separable groups.
Approximately transitive flows and ITPFI factors
Authors: Connes A. , Woods E. J. 
Published: September 2008

AbstractWe define a new property of a Borel group action on a Lebesgue measure space, which we call approximate transitivity. Our main results are (i) a type III0 hyperfinite factor is ITPFI if and only if its flow of weights is approximately transitive, and (ii) for ergodic transformations preserving a finite measure, approximate transitivity implies zero entropy.
Periodic points for piecewise monotonic transformations
Authors: Hofbauer Franz 
Published: September 2008

AbstractPeriodic points of piecewise monotonic transformations are investigated using an oriented graph, whose closed paths represent the periodic orbits of the transformation. In the first part it is shown that the inverse of the ζ-function is a kind of characteristic polynomial of this graph, which is a power series if the graph is infinite. In the second part, the sets are determined, which can occur as{withandwhereTis a monotonic mod one transformation.
Manifolds with non-positive curvature
Authors: Burns K. , Katok A. , Ballman W. , Brin M. , Eberlein P. , Osserman R. 
Published: September 2008

AbstractThis is an extended report on a problem session about geodesic flows held on May 30, 1984 at MSRI, Berkeley. The list of six authors reflects the principal participants in the discussion. Contributions of other participants are mentioned in the text. The session was chaired by A. Katok; this report was prepared by K. Burns in collaboration with A. Katok.
The chain recurrent set, attractors, and explosions
Authors: Block Louis , Franke John E. 
Published: September 2008

AbstractCharles Conley has shown that for a flow on a compact metric space, a point x is chain recurrent if and only if any attractor which contains the & ω-limit set of x also contains x. In this paper we show that the same statement holds for a continuous map of a compact metric space to itself, and additional equivalent conditions can be given. A stronger result is obtained if the space is locally connected.It follows, as a special case, that if a map of the circle to itself has no periodic points then every point is chain recurrent. Also, for any homeomorphism of the circle to itself, the chain recurrent set is either the set of periodic points or the entire circle. Finally, we use the equivalent conditions mentioned above to show that for any continuous map f of a compact space to itself, if the non-wandering set equals the chain recurrent set then f does not permit Ω-explosions. The converse holds on manifolds.
On the measurable dynamics of z → ez
Authors: Ghys Etienne , Goldberg Lisa R. , Sullivan Dennis P. 
Published: September 2008

AbstractWe study the measure theoretic properties of the complex exponential map E(z) = ez.An particular, we show that the equivalence relation generated by E is recurrent and that E has no quasi-conformal deformations. This enables us to give some information concerning Devaney's semi-conjugacy between E and the shift map on sequences of integers.
On upcrossing inequalities for subadditive superstationary processes
Authors: Krawczak Michael 
Published: September 2008

AbstractBishop [2]has given a proof of Birkhoff's ergodic theorem by establishing upcrossing inequalities similar to those of Doob. Such inequalities can be considered as quantitative improvements of convergence theorems: while convergence a.e. means that the number of upcrossings of any interval is a.e. finite, they assert integrability and prove bounds for the integrals. The main point of this paper is to prove upcrossing inequalities for the class of subadditive superstationary processes introduced by Abid [1] as a common generalization of Kingman's [5] subadditive stationary processes and Krengel's [6] superstationary processes. We make use of ideas of Smeltzer [7] who handled the subadditive stationary discrete parameter case in his unpublished thesis. In the continuous parameter case our upcrossing inequality requires more restrictive conditions than the corresponding convergence theorem, due to Hachem [3]. We actually show by example that the number of upcrossings need not be integrable under the assumptions of Hachem even for additive stationary processes.
Problems on rigidity of group actions and cocycles
Authors: Hurder S. 
Published: September 2008

AbstractA conference on the interaction of ergodic theory, differential geometry and the theory of Lie Groups was held at the Mathematical Sciences Research Institute from May 24 to June 1, 1984. This is a report of the problem session organized by A. Katok and R. Zimmer and held on May 25, 1984 dealing with the topics in the title. Another problem session was centred on the rigidity of manifolds of non-positive curvature and related topics concerning their geodesic flows. This is reported on by K. Burns and A. Karok separately [2].
Twist periodic orbits and topological entropy for continuous maps of the circle of degree one which have a fixed point
Authors: Alsedà Lluís , Llibre Jaume , Misiurewicz Michał , Simó Carles 
Published: September 2008

AbstractLet f be a continuous map from the circle into itself of degree one, having a periodic orbit of rotation number p/q ≠ 0. If (p, q) = 1 then we prove that f has a twist periodic orbit of period q and rotation number p/q (i.e. a periodic orbit which behaves as a rotation of the circle with angle 2πp/q). Also, for this map we give the best lower bound of the topological entropy as a function of the rotation interval if one of the endpoints of the interval is an integer.
Transitivity and the centre for maps of the circle
Authors: Coven Ethan M. , Mulvey Irene 
Published: September 2008

AbstractWe study the dynamics of continuous maps of the circle with periodic points. We show that the centre is the closure of the periodic points and that the depth of the centre is at most two. We also characterize the property that every power is transitive in terms of transitivity of a single power and some periodic data.
Smoothing continuous flows on two-manifolds and recurrences
Authors: Gutierrez Carlos 
Published: September 2008

AbstractLet φ: ℝ × M → M be a continuous flow on a compact C∞ two-manifold M. It is proved that there exists a C1 flow ψ on M which is topologically equivalent to φ, and that the following conditions are equivalent:(a) any minimal set of φ is trivial;(b) φ is topologically equivalent to a C2 flow;(c) φ is topologically equivalent to a C∞ flow.Also proved is a structure and an existence theorem for continuous flows with non-trivial recurrence.
On strong shift equivalence over a Boolean semiring
Authors: Kim Ki Hang , Roush Fred W. 
Published: September 2008

AbstractShift equivalence is the relation between A, B that there exists S, R, n > 0 with RA = BR, AS = SB, SR = An, RS = Bn. Strong shift equivalence is the equivalence relation generated by these equations with n = 1. We prove that for many Boolean matrices strong shift equivalence is characterized by shift equivalence and a trace condition. However, we also show that if A is strongly shift equivalent to B, then there exists a homomorphism from an iterated directed edge graph of A to the graph of B preserving the traces of powers. This yields results on colourings of iterated directed edge graphs and might distinguish new strong equivalence classes.
Hölder continuous paths and hyperbolic toral automorphisms
Authors: Irwin M. C. 
Published: September 2008

AbstractLet f:Tn→Tn (n ≥ 3) be a hyperbolic toral automorphism. Let A be the set of α > 0 such that there is a Hölder continuous path of index α in Tn with 1-dimensional orbit-closure under f We prove that α0 = sup A can be expressed in terms of the eigenvalues of f and that α0 ∈ A if and only if α0 < 1.
Topological conjugacy for sofic systems
Authors: Nasu Masakazu 
Published: September 2008

AbstractWe prove that any topological conjugacy between subshifts is decomposed into the product of‘bipartite codes’, and obtain a natural generalization of Williams' theorem to sofic systems: two sofic systems are topologically conjugate iff the ‘representation matrices’ of the right [left] Krieger covers for them are ‘strong shift equivalent’ within right [left] Krieger covers; a similar result with respect to Fischer covers holds for transitive sofic systems.
The commutant is the weak closure of the powers, for rank-1 transformations
Authors: King Jonathan 
Published: September 2008

AbstractIn the class of rank-1 transformations, there is a strong dichotomy. For such a T, the commutant is either irivial, consisting only of the powers of T, or is uncountable. In addition, the commutant semigroup, C(T), is in fact a group. As a consequence, the notion of weak isomorphism between two transformations is equivalent to isomorphism, if at least one of the transformations is rank-1. In § 2, we show that any proper factor of a rank-1 must be rigid. Hence, neither Ornstein's rank-1 mixing nor Chacón's transformation, can be a factor of a rank-1.
Equilibrium measures for rational maps
Authors: Lopes Artur Oscar 
Published: September 2008

AbstractFor a polynomial map the measure of maximal entropy is the equilibrium measure for the logarithm potential in the Julia set [1], [4].Here we will show that in the case where f is a rational map such that f(∞) = ∞ and the Julia set is bounded, then the two measures mentioned above are equal if and only if f is a polynomial.