Displaying similar documents to “Mean value densities for temperatures”

Construction of an Uncountable Difference between Φ(B) and Φ f ( B )

Josh Campbell, David Swanson (2008)

Bulletin of the Polish Academy of Sciences. Mathematics

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We construct a set B and homeomorphism f where f and f - 1 have property N such that the symmetric difference between the sets of density points and of f-density points of B is uncountable.

Kempisty's theorem for the integral product quasicontinuity

Zbigniew Grande (2006)

Colloquium Mathematicae

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A function f: ℝⁿ → ℝ satisfies the condition Q i ( x ) (resp. Q s ( x ) , Q o ( x ) ) at a point x if for each real r > 0 and for each set U ∋ x open in the Euclidean topology of ℝⁿ (resp. strong density topology, ordinary density topology) there is an open set I such that I ∩ U ≠ ∅ and | ( 1 / μ ( U I ) ) U I f ( t ) d t - f ( x ) | < r . Kempisty’s theorem concerning the product quasicontinuity is investigated for the above notions.

Continuity of halo functions associated to homothecy invariant density bases

Oleksandra Beznosova, Paul Hagelstein (2014)

Colloquium Mathematicae

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Let be a collection of bounded open sets in ℝⁿ such that, for any x ∈ ℝⁿ, there exists a set U ∈ of arbitrarily small diameter containing x. The collection is said to be a density basis provided that, given a measurable set A ⊂ ℝⁿ, for a.e. x ∈ ℝⁿ we have l i m k 1 / | R k | R k χ A = χ A ( x ) for any sequence R k of sets in containing x whose diameters tend to 0. The geometric maximal operator M associated to is defined on L¹(ℝⁿ) by M f ( x ) = s u p x R 1 / | R | R | f | . The halo function ϕ of is defined on (1,∞) by ϕ ( u ) = s u p 1 / | A | | x : M χ A ( x ) > 1 / u | : 0 < | A | < and on [0,1] by ϕ(u) = u. It is shown...

A density version of the Carlson–Simpson theorem

Pandelis Dodos, Vassilis Kanellopoulos, Konstantinos Tyros (2014)

Journal of the European Mathematical Society

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We prove a density version of the Carlson–Simpson Theorem. Specifically we show the following. For every integer k 2 and every set A of words over k satisfying lim sup n | A [ k ] n | / k n > 0 there exist a word c over k and a sequence ( w n ) of left variable words over k such that the set c { c w 0 ( a 0 ) . . . w n ( a n ) : n and a 0 , . . . , a n [ k ] } is contained in A . While the result is infinite-dimensional its proof is based on an appropriate finite and quantitative version, also obtained in the paper.

Estimation of the density of a determinantal process

Yannick Baraud (2013)

Confluentes Mathematici

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We consider the problem of estimating the density Π of a determinantal process N from the observation of n independent copies of it. We use an aggregation procedure based on robust testing to build our estimator. We establish non-asymptotic risk bounds with respect to the Hellinger loss and deduce, when n goes to infinity, uniform rates of convergence over classes of densities Π of interest.

Maximal upper asymptotic density of sets of integers with missing differences from a given set

Ram Krishna Pandey (2015)

Mathematica Bohemica

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Let M be a given nonempty set of positive integers and S any set of nonnegative integers. Let δ ¯ ( S ) denote the upper asymptotic density of S . We consider the problem of finding μ ( M ) : = sup S δ ¯ ( S ) , where the supremum is taken over all sets S satisfying that for each a , b S , a - b M . In this paper we discuss the values and bounds of μ ( M ) where M = { a , b , a + n b } for all even integers and for all sufficiently large odd integers n with a < b and gcd ( a , b ) = 1 .

Density estimation via best L 2 -approximation on classes of step functions

Dietmar Ferger, John Venz (2017)

Kybernetika

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We establish consistent estimators of jump positions and jump altitudes of a multi-level step function that is the best L 2 -approximation of a probability density function f . If f itself is a step-function the number of jumps may be unknown.

Coprimality of integers in Piatetski-Shapiro sequences

Watcharapon Pimsert, Teerapat Srichan, Pinthira Tangsupphathawat (2023)

Czechoslovak Mathematical Journal

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We use the estimation of the number of integers n such that n c belongs to an arithmetic progression to study the coprimality of integers in c = { n c } n , c > 1 , c .

Density of smooth maps for fractional Sobolev spaces W s , p into simply connected manifolds when s 1

Pierre Bousquet, Augusto C. Ponce, Jean Van Schaftingen (2013)

Confluentes Mathematici

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Given a compact manifold N n ν and real numbers s 1 and 1 p &lt; , we prove that the class C ( Q ¯ m ; N n ) of smooth maps on the cube with values into N n is strongly dense in the fractional Sobolev space W s , p ( Q m ; N n ) when N n is s p simply connected. For s p integer, we prove weak sequential density of C ( Q ¯ m ; N n ) when N n is s p - 1 simply connected. The proofs are based on the existence of a retraction of ν onto N n except for a small subset of N n and on a pointwise estimate of fractional derivatives of composition of maps in W s , p W 1 , s p .

The local index density of the perturbed de Rham complex

Jesús Álvarez López, Peter B. Gilkey (2021)

Czechoslovak Mathematical Journal

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A perturbation of the de Rham complex was introduced by Witten for an exact 1-form Θ and later extended by Novikov for a closed 1-form on a Riemannian manifold M . We use invariance theory to show that the perturbed index density is independent of Θ ; this result was established previously by J. A. Álvarez López, Y. A. Kordyukov and E. Leichtnam (2020) using other methods. We also show the higher order heat trace asymptotics of the perturbed de Rham complex exhibit nontrivial dependence...

Cardinal invariants for κ-box products: weight, density character and Suslin number

W. W. Comfort, Ivan S. Gotchev

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The symbol ( X I ) κ (with κ ≥ ω) denotes the space X I : = i I X i with the κ-box topology; this has as base all sets of the form U = i I U i with U i open in X i and with | i I : U i X i | < κ . The symbols w, d and S denote respectively the weight, density character and Suslin number. Generalizing familiar classical results, the authors show inter alia: Theorem 3.1.10(b). If κ ≤ α⁺, |I| = α and each X i contains the discrete space 0,1 and satisfies w ( X i ) α , then w ( X κ ) = α < κ . Theorem 4.3.2. If ω κ | I | 2 α and X = ( D ( α ) ) I with D(α) discrete, |D(α)| = α, then d ( ( X I ) κ ) = α < κ . Corollaries 5.2.32(a)...

Selivanovski hard sets are hard

Janusz Pawlikowski (2015)

Fundamenta Mathematicae

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Let H Z 2 ω . For n ≥ 2, we prove that if Selivanovski measurable functions from 2 ω to Z give as preimages of H all Σₙ¹ subsets of 2 ω , then so do continuous injections.

Local density of diffeomorphisms with large centralizers

Christian Bonatti, Sylvain Crovisier, Gioia M. Vago, Amie Wilkinson (2008)

Annales scientifiques de l'École Normale Supérieure

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Given any compact manifold M , we construct a non-empty open subset 𝒪 of the space Diff 1 ( M ) of C 1 -diffeomorphisms and a dense subset 𝒟 𝒪 such that the centralizer of every diffeomorphism in 𝒟 is uncountable, hence non-trivial.