Displaying similar documents to “Characterization of local dimension functions of subsets of d

Infinite Iterated Function Systems Depending on a Parameter

Ludwik Jaksztas (2007)

Bulletin of the Polish Academy of Sciences. Mathematics

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This paper is motivated by the problem of dependence of the Hausdorff dimension of the Julia-Lavaurs sets J 0 , σ for the map f₀(z) = z²+1/4 on the parameter σ. Using homographies, we imitate the construction of the iterated function system (IFS) whose limit set is a subset of J 0 , σ , given by Urbański and Zinsmeister. The closure of the limit set of our IFS ϕ σ , α n , k is the closure of some family of circles, and if the parameter σ varies, then the behavior of the limit set is similar to the behavior of...

On the Separation Dimension of K ω

Yasunao Hattori, Jan van Mill (2013)

Bulletin of the Polish Academy of Sciences. Mathematics

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We prove that t r t K ω > ω + 1 , where trt stands for the transfinite extension of Steinke’s separation dimension. This answers a question of Chatyrko and Hattori.

Homogeneity and non-coincidence of Hausdorff and box dimensions for subsets of ℝⁿ

Anders Nilsson, Peter Wingren (2007)

Studia Mathematica

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A class of subsets of ℝⁿ is constructed that have certain homogeneity and non-coincidence properties with respect to Hausdorff and box dimensions. For each triple (r,s,t) of numbers in the interval (0,n] with r < s < t, a compact set K is constructed so that for any non-empty subset U relatively open in K, we have ( d i m H ( U ) , d i m ̲ B ( U ) , d i m ¯ B ( U ) ) = ( r , s , t ) . Moreover, 2 - n H r ( K ) 2 n r / 2 .

On the continuity of the Hausdorff dimension of the Julia-Lavaurs sets

Ludwik Jaksztas (2011)

Fundamenta Mathematicae

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Let f₀(z) = z²+1/4. We denote by ₀ the set of parameters σ ∈ ℂ for which the critical point 0 escapes from the filled-in Julia set K(f₀) in one step by the Lavaurs map g σ . We prove that if σ₀ ∈ ∂₀, then the Hausdorff dimension of the Julia-Lavaurs set J 0 , σ is continuous at σ₀ as the function of the parameter σ ¯ if and only if H D ( J 0 , σ ) 4 / 3 . Since H D ( J 0 , σ ) > 4 / 3 on a dense set of parameters which correspond to preparabolic points, the lower semicontinuity implies the continuity of H D ( J 0 , σ ) on an open and dense subset of...

On the Hausdorff Dimension of Topological Subspaces

Tomasz Szarek, Maciej Ślęczka (2006)

Bulletin of the Polish Academy of Sciences. Mathematics

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It is shown that every Polish space X with d i m T X d admits a compact subspace Y such that d i m H Y d where d i m T and d i m H denote the topological and Hausdorff dimensions, respectively.

Univoque sets for real numbers

Fan Lü, Bo Tan, Jun Wu (2014)

Fundamenta Mathematicae

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For x ∈ (0,1), the univoque set for x, denoted (x), is defined to be the set of β ∈ (1,2) such that x has only one representation of the form x = x₁/β + x₂/β² + ⋯ with x i 0 , 1 . We prove that for any x ∈ (0,1), (x) contains a sequence β k k 1 increasing to 2. Moreover, (x) is a Lebesgue null set of Hausdorff dimension 1; both (x) and its closure ( x ) ¯ are nowhere dense.

A two-dimensional univoque set

Martijn de Vrie, Vilmos Komornik (2011)

Fundamenta Mathematicae

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Let J ⊂ ℝ² be the set of couples (x,q) with q > 1 such that x has at least one representation of the form x = i = 1 c i q - i with integer coefficients c i satisfying 0 c i < q , i ≥ 1. In this case we say that ( c i ) = c c . . . is an expansion of x in base q. Let U be the set of couples (x,q) ∈ J such that x has exactly one expansion in base q. In this paper we deduce some topological and combinatorial properties of the set U. We characterize the closure of U, and we determine its Hausdorff dimension. For (x,q) ∈ J, we also...

The (dis)connectedness of products of Hausdorff spaces in the box topology

Vitalij A. Chatyrko (2021)

Commentationes Mathematicae Universitatis Carolinae

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In this paper the following two propositions are proved: (a) If X α , α A , is an infinite system of connected spaces such that infinitely many of them are nondegenerated completely Hausdorff topological spaces then the box product α A X α can be decomposed into continuum many disjoint nonempty open subsets, in particular, it is disconnected. (b) If X α , α A , is an infinite system of Brown Hausdorff topological spaces then the box product α A X α is also Brown Hausdorff, and hence, it is connected. A space...

Birational positivity in dimension 4

Behrouz Taji (2014)

Annales de l’institut Fourier

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In this paper we prove that for a nonsingular projective variety of dimension at most 4 and with non-negative Kodaira dimension, the Kodaira dimension of coherent subsheaves of Ω p is bounded from above by the Kodaira dimension of the variety. This implies the finiteness of the fundamental group for such an X provided that X has vanishing Kodaira dimension and non-trivial holomorphic Euler characteristic.

The growth speed of digits in infinite iterated function systems

Chun-Yun Cao, Bao-Wei Wang, Jun Wu (2013)

Studia Mathematica

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Let f n 1 be an infinite iterated function system on [0,1] satisfying the open set condition with the open set (0,1) and let Λ be its attractor. Then to any x ∈ Λ (except at most countably many points) corresponds a unique sequence a ( x ) n 1 of integers, called the digit sequence of x, such that x = l i m n f a ( x ) f a ( x ) ( 1 ) . We investigate the growth speed of the digits in a general infinite iterated function system. More precisely, we determine the dimension of the set x Λ : a ( x ) B ( n 1 ) , l i m n a ( x ) = for any infinite subset B ⊂ ℕ, a question posed by...

On the continuity of Hausdorff dimension of Julia sets and similarity between the Mandelbrot set and Julia sets

Juan Rivera-Letelier (2001)

Fundamenta Mathematicae

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Given d ≥ 2 consider the family of polynomials P c ( z ) = z d + c for c ∈ ℂ. Denote by J c the Julia set of P c and let d = c | J c i s c o n n e c t e d be the connectedness locus; for d = 2 it is called the Mandelbrot set. We study semihyperbolic parameters c d : those for which the critical point 0 is not recurrent by P c and without parabolic cycles. The Hausdorff dimension of J c , denoted by H D ( J c ) , does not depend continuously on c at such c d ; on the other hand the function c H D ( J c ) is analytic in - d . Our first result asserts that there is still some...

On dimensionally restricted maps

H. Murat Tuncali, Vesko Valov (2002)

Fundamenta Mathematicae

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Let f: X → Y be a closed n-dimensional surjective map of metrizable spaces. It is shown that if Y is a C-space, then: (1) the set of all maps g: X → ⁿ with dim(f △ g) = 0 is uniformly dense in C(X,ⁿ); (2) for every 0 ≤ k ≤ n-1 there exists an F σ -subset A k of X such that d i m A k k and the restriction f | ( X A k ) is (n-k-1)-dimensional. These are extensions of theorems by Pasynkov and Toruńczyk, respectively, obtained for finite-dimensional spaces. A generalization of a result due to Dranishnikov and Uspenskij...

An obstruction to p -dimension

Nicolas Monod, Henrik Densing Petersen (2014)

Annales de l’institut Fourier

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Let G be any group containing an infinite elementary amenable subgroup and let 2 &lt; p &lt; . We construct an exhaustion of p G by closed invariant subspaces which all intersect trivially a fixed non-trivial closed invariant subspace. This is an obstacle to p -dimension and gives an answer to a question of Gaboriau.

Universal acyclic resolutions for arbitrary coefficient groups

Michael Levin (2003)

Fundamenta Mathematicae

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We prove that for every compactum X and every integer n ≥ 2 there are a compactum Z of dimension ≤ n+1 and a surjective U V n - 1 -map r: Z → X such that for every abelian group G and every integer k ≥ 2 such that d i m G X k n we have d i m G Z k and r is G-acyclic.

Some results on Poincaré sets

Min-wei Tang, Zhi-Yi Wu (2020)

Czechoslovak Mathematical Journal

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It is known that a set H of positive integers is a Poincaré set (also called intersective set, see I. Ruzsa (1982)) if and only if dim ( X H ) = 0 , where X H : = x = n = 1 x n 2 n : x n { 0 , 1 } , x n x n + h = 0 for all n 1 , h H and dim denotes the Hausdorff dimension (see C. Bishop, Y. Peres (2017), Theorem 2.5.5). In this paper we study the set X H by replacing 2 with b > 2 . It is surprising that there are some new phenomena to be worthy of studying. We study them and give several examples to explain our results.

Strong bifurcation loci of full Hausdorff dimension

Thomas Gauthier (2012)

Annales scientifiques de l'École Normale Supérieure

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In the moduli space d of degree  d rational maps, the bifurcation locus is the support of a closed ( 1 , 1 ) positive current T bif which is called the bifurcation current. This current gives rise to a measure μ bif : = ( T bif ) 2 d - 2 whose support is the seat of strong bifurcations. Our main result says that supp ( μ bif ) has maximal Hausdorff dimension 2 ( 2 d - 2 ) . As a consequence, the set of degree  d rational maps having ( 2 d - 2 ) distinct neutral cycles is dense in a set of full Hausdorff dimension.

Normal number constructions for Cantor series with slowly growing bases

Dylan Airey, Bill Mance, Joseph Vandehey (2016)

Czechoslovak Mathematical Journal

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Let Q = ( q n ) n = 1 be a sequence of bases with q i 2 . In the case when the q i are slowly growing and satisfy some additional weak conditions, we provide a construction of a number whose Q -Cantor series expansion is both Q -normal and Q -distribution normal. Moreover, this construction will result in a computable number provided we have some additional conditions on the computability of Q , and from this construction we can provide computable constructions of numbers with atypical normality properties. ...

Finitistic dimension and restricted injective dimension

Dejun Wu (2015)

Czechoslovak Mathematical Journal

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We study the relations between finitistic dimensions and restricted injective dimensions. Let R be a ring and T a left R -module with A = End R T . If R T is selforthogonal, then we show that rid ( T A ) findim ( A A ) findim ( R T ) + rid ( T A ) . Moreover, if R is a left noetherian ring and T is a finitely generated left R -module with finite injective dimension, then rid ( T A ) findim ( A A ) fin . inj . dim ( R R ) + rid ( T A ) . Also we show by an example that the restricted injective dimensions of a module may be strictly smaller than the Gorenstein injective dimension.

T 2 and T 3 objects at p in the category of proximity spaces

Muammer Kula, Samed Özkan (2020)

Mathematica Bohemica

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In previous papers, various notions of pre-Hausdorff, Hausdorff and regular objects at a point p in a topological category were introduced and compared. The main objective of this paper is to characterize each of these notions of pre-Hausdorff, Hausdorff and regular objects locally in the category of proximity spaces. Furthermore, the relationships that arise among the various Pre T 2 , T i , i = 0 , 1 , 2 , 3 , structures at a point p are investigated. Finally, we examine the relationships between the generalized...

L p -improving properties of measures of positive energy dimension

Kathryn E. Hare, Maria Roginskaya (2005)

Colloquium Mathematicae

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A measure is called L p -improving if it acts by convolution as a bounded operator from L p to L q for some q > p. Positive measures which are L p -improving are known to have positive Hausdorff dimension. We extend this result to complex L p -improving measures and show that even their energy dimension is positive. Measures of positive energy dimension are seen to be the Lipschitz measures and are characterized in terms of their improving behaviour on a subset of L p -functions.