Displaying similar documents to “Inequalities for radial Blaschke-Minkowski homomorphisms”

Poincaré Inequalities and Moment Maps

Bo’az Klartag (2013)

Annales de la faculté des sciences de Toulouse Mathématiques

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We discuss a method for obtaining Poincaré-type inequalities on arbitrary convex bodies in n . Our technique involves a dual version of Bochner’s formula and a certain moment map, and it also applies to some non-convex sets. In particular, we generalize the central limit theorem for convex bodies to a class of non-convex domains, including the unit balls of p -spaces in n for 0 < p < 1 .

Concerning Sets of the First Baire Category with Respect to Different Metrics

Maria Moszyńska, Grzegorz Sójka (2010)

Bulletin of the Polish Academy of Sciences. Mathematics

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We prove that if ϱ H and δ are the Hausdorff metric and the radial metric on the space ⁿ of star bodies in ℝ, with 0 in the kernel and with radial function positive and continuous, then a family ⊂ ⁿ that is meager with respect to ϱ H need not be meager with respect to δ. Further, we show that both the family of fractal star bodies and its complement are dense in ⁿ with respect to δ.

Moser-Trudinger and logarithmic HLS inequalities for systems

Itai Shafrir, Gershon Wolansky (2005)

Journal of the European Mathematical Society

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We prove several optimal Moser–Trudinger and logarithmic Hardy–Littlewood–Sobolev inequalities for systems in two dimensions. These include inequalities on the sphere S 2 , on a bounded domain Ω 2 and on all of 2 . In some cases we also address the question of existence of minimizers.

The role of Onofri type inequalities in the symmetry properties of extremals for Caffarelli-Kohn-Nirenberg inequalities, in two space dimensions

Jean Dolbeault, Maria J. Esteban, Gabriella Tarantello (2008)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

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We first discuss a class of inequalities of Onofri type depending on a parameter, in the two-dimensional Euclidean space. The inequality holds for radial functions if the parameter is larger than - 1 . Without symmetry assumption, it holds if and only if the parameter is in the interval ( - 1 , 0 ] . The inequality gives us some insight on the symmetry breaking phenomenon for the extremal functions of the Caffarelli-Kohn-Nirenberg inequality, in two space dimensions. In fact, for suitable sets of...

Circumradius versus side lengths of triangles in linear normed spaces

Gennadiy Averkov (2007)

Colloquium Mathematicae

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Given a planar convex body B centered at the origin, we denote by ℳ ²(B) the Minkowski plane (i.e., two-dimensional linear normed space) with the unit ball B. For a triangle T in ℳ ²(B) we denote by R B ( T ) the least possible radius of a Minkowskian ball enclosing T. We remark that in the terminology of location science R B ( T ) is the optimum of the minimax location problem with distance induced by B and vertices of T as existing facilities (see, for instance, [HM03] and the references therein)....

On the ψ₂-behaviour of linear functionals on isotropic convex bodies

G. Paouris (2005)

Studia Mathematica

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The slicing problem can be reduced to the study of isotropic convex bodies K with d i a m ( K ) c n L K , where L K is the isotropic constant. We study the ψ₂-behaviour of linear functionals on this class of bodies. It is proved that | | · , θ | | ψ C L K for all θ in a subset U of S n - 1 with measure σ(U) ≥ 1 - exp(-c√n). However, there exist isotropic convex bodies K with uniformly bounded geometric distance from the Euclidean ball, such that m a x θ S n - 1 | | · , θ | | ψ c n L K . In a different direction, we show that good average ψ₂-behaviour of linear functionals...

A sharp isoperimetric inequality in the plane

Angelo Alvino, Vincenzo Ferone, Carlo Nitsch (2011)

Journal of the European Mathematical Society

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We show that among all the convex bounded domain in m a t h b b R 2 having an assigned Fraenkel asymmetry index, there exists only one convex set (up to a similarity) which minimizes the isoperimetric deficit. We also show how to construct this set. The result can be read as a sharp improvement of the isoperimetric inequality for convex planar domain.

A new characterization of the Sobolev space

Piotr Hajłasz (2003)

Studia Mathematica

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The purpose of this paper is to provide a new characterization of the Sobolev space W 1 , 1 ( ) . We also show a new proof of the characterization of the Sobolev space W 1 , p ( ) , 1 ≤ p < ∞, in terms of Poincaré inequalities.

Pairs of convex bodies in a hyperspace over a Minkowski two-dimensional space joined by a unique metric segment

Agnieszka Bogdewicz, Jerzy Grzybowski (2009)

Banach Center Publications

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Let ( , | | · | | ) be a Minkowski space with a unit ball and let ϱ H be the Hausdorff metric induced by | | · | | in the hyperspace of convex bodies (nonempty, compact, convex subsets of ℝ). R. Schneider [RSP] characterized pairs of elements of which can be joined by unique metric segments with respect to ϱ H B for the Euclidean unit ball Bⁿ. We extend Schneider’s theorem to the hyperspace ( ² , ϱ H ) over any two-dimensional Minkowski space.

Reduced spherical polygons

Marek Lassak (2015)

Colloquium Mathematicae

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For every hemisphere K supporting a spherically convex body C of the d-dimensional sphere S d we consider the width of C determined by K. By the thickness Δ(C) of C we mean the minimum of the widths of C over all supporting hemispheres K of C. A spherically convex body R S d is said to be reduced provided Δ(Z) < Δ(R) for every spherically convex body Z ⊂ R different from R. We characterize reduced spherical polygons on S². We show that every reduced spherical polygon is of thickness at...

Lieb–Thirring inequalities on the half-line with critical exponent

Tomas Ekholm, Rupert Frank (2008)

Journal of the European Mathematical Society

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We consider the operator - d 2 / d r 2 - V in L 2 ( + ) with Dirichlet boundary condition at the origin. For the moments of its negative eigenvalues we prove the bound tr ( - d 2 / d r 2 - V ) - γ C γ , α + ( V ( r ) - 1 / ( 4 r 2 ) ) + γ + ( 1 + α ) / 2 r α d r for any α [ 0 , 1 ) and γ ( 1 - α ) / 2 . This includes a Lieb-Thirring inequality in the critical endpoint case.

A pair of linear functional inequalities and a characterization of L p -norm

Dorota Krassowska, Janusz Matkowski (2005)

Annales Polonici Mathematici

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It is shown that, under some general algebraic conditions on fixed real numbers a,b,α,β, every solution f:ℝ → ℝ of the system of functional inequalities f(x+a) ≤ f(x)+α, f(x+b) ≤ f(x)+β that is continuous at some point must be a linear function (up to an additive constant). Analogous results for three other similar simultaneous systems are presented. An application to a characterization of L p -norm is given.

Sharp Norm Inequalities for Martingales and their Differential Subordinates

Adam Osękowski (2007)

Bulletin of the Polish Academy of Sciences. Mathematics

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Suppose f = (fₙ), g = (gₙ) are martingales with respect to the same filtration, satisfying | f - f n - 1 | | g - g n - 1 | , n = 1,2,..., with probability 1. Under some assumptions on f₀, g₀ and an additional condition that one of the processes is nonnegative, some sharp inequalities between the pth norms of f and g, 0 < p < ∞, are established. As an application, related sharp inequalities for stochastic integrals and harmonic functions are obtained.

Sharp moment inequalities for differentially subordinated martingales

Adam Osękowski (2010)

Studia Mathematica

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We determine the optimal constants C p , q in the moment inequalities | | g | | p C p , q | | f | | q , 1 ≤ p< q< ∞, where f = (fₙ), g = (gₙ) are two martingales, adapted to the same filtration, satisfying |dgₙ| ≤ |dfₙ|, n = 0,1,2,..., with probability 1. Furthermore, we establish related sharp estimates ||g||₁ ≤ supₙΦ(|fₙ|) + L(Φ), where Φ is an increasing convex function satisfying certain growth conditions and L(Φ) depends only on Φ.

Asymptotic behaviour of averages of k-dimensional marginals of measures on ℝⁿ

Jesús Bastero, Julio Bernués (2009)

Studia Mathematica

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We study the asymptotic behaviour, as n → ∞, of the Lebesgue measure of the set x K : | P E ( x ) | t for a random k-dimensional subspace E ⊂ ℝⁿ and an isotropic convex body K ⊂ ℝⁿ. For k growing slowly to infinity, we prove it to be close to the suitably normalised Gaussian measure in k of a t-dilate of the Euclidean unit ball. Some of the results hold for a wider class of probabilities on ℝⁿ.

Volumetric invariants and operators on random families of Banach spaces

Piotr Mankiewicz, Nicole Tomczak-Jaegermann (2003)

Studia Mathematica

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The geometry of random projections of centrally symmetric convex bodies in N is studied. It is shown that if for such a body K the Euclidean ball B N is the ellipsoid of minimal volume containing it and a random n-dimensional projection B = P H ( K ) is “far” from P H ( B N ) then the (random) body B is as “rigid” as its “distance” to P H ( B N ) permits. The result holds for the full range of dimensions 1 ≤ n ≤ λN, for arbitrary λ ∈ (0,1).

Majorization of sequences, sharp vector Khinchin inequalities, and bisubharmonic functions

Albert Baernstein II, Robert C. Culverhouse (2002)

Studia Mathematica

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Let X = i = 1 k a i U i , Y = i = 1 k b i U i , where the U i are independent random vectors, each uniformly distributed on the unit sphere in ℝⁿ, and a i , b i are real constants. We prove that if b ² i is majorized by a ² i in the sense of Hardy-Littlewood-Pólya, and if Φ: ℝⁿ → ℝ is continuous and bisubharmonic, then EΦ(X) ≤ EΦ(Y). Consequences include most of the known sharp L ² - L p Khinchin inequalities for sums of the form X. For radial Φ, bisubharmonicity is necessary as well as sufficient for the majorization inequality to always hold. Counterparts...

A sharp bound for a sine polynomial

Horst Alzer, Stamatis Koumandos (2003)

Colloquium Mathematicae

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We prove that | k = 1 n s i n ( ( 2 k - 1 ) x ) / k | < S i ( π ) = 1 . 8519 . . . for all integers n ≥ 1 and real numbers x. The upper bound Si(π) is best possible. This result refines inequalities due to Fejér (1910) and Lenz (1951).

Carathéodory solutions of hyperbolic functional differential inequalities with first order derivatives

Adrian Karpowicz (2008)

Annales Polonici Mathematici

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We consider the Darboux problem for a functional differential equation: ( ² u ) / ( x y ) ( x , y ) = f ( x , y , u ( x , y ) , u ( x , y ) , u / x ( x , y ) , u / y ( x , y ) ) a.e. in [0,a]×[0,b], u(x,y) = ψ(x,y) on [-a₀,a]×[-b₀,b]∖(0,a]×(0,b], where the function u ( x , y ) : [ - a , 0 ] × [ - b , 0 ] k is defined by u ( x , y ) ( s , t ) = u ( s + x , t + y ) for (s,t) ∈ [-a₀,0]×[-b₀,0]. We give a few theorems about weak and strong inequalities for this problem. We also discuss the case where the right-hand side of the differential equation is linear.

Geometry of numbers in adele spaces

R. B. McFeat

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CONTENTSPart I1. Introduction...................................................................................................................................................... 52. Preliminaries.................................................................................................................................................. 62.1. Notation...........................................................................................................................................................

Gagliardo-Nirenberg inequalities in logarithmic spaces

Agnieszka Kałamajska, Katarzyna Pietruska-Pałuba (2006)

Colloquium Mathematicae

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We obtain interpolation inequalities for derivatives: M q , α ( | f ( x ) | ) d x C [ M p , β ( Φ ( x , | f | , | ( 2 ) f | ) ) d x + M r , γ ( Φ ( x , | f | , | ( 2 ) f | ) ) d x ] , and their counterparts expressed in Orlicz norms: ||∇f||²(q,α) ≤ C||Φ₁(x,|f|,|∇(2)f|)||(p,β) ||Φ₂(x,|f|,|∇(2)f|)||(r,γ) , where | | · | | ( s , κ ) is the Orlicz norm relative to the function M s , κ ( t ) = t s ( l n ( 2 + t ) ) κ . The parameters p,q,r,α,β,γ and the Carathéodory functions Φ₁,Φ₂ are supposed to satisfy certain consistency conditions. Some of the classical Gagliardo-Nirenberg inequalities follow as a special case. Gagliardo-Nirenberg inequalities in logarithmic spaces...

The minimal operator and the geometric maximal operator in ℝⁿ

David Cruz-Uribe, SFO (2001)

Studia Mathematica

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We prove two-weight norm inequalities in ℝⁿ for the minimal operator f ( x ) = i n f Q x 1 / | Q | Q | f | d y , extending to higher dimensions results obtained by Cruz-Uribe, Neugebauer and Olesen [8] on the real line. As an application we extend to ℝⁿ weighted norm inequalities for the geometric maximal operator M f ( x ) = s u p Q x e x p ( 1 / | Q | Q l o g | f | d x ) , proved by Yin and Muckenhoupt [27]. We also give norm inequalities for the centered minimal operator, study powers of doubling weights and give sufficient conditions for the geometric maximal operator to be equal...

Lower bounds for Schrödinger operators in H¹(ℝ)

Ronan Pouliquen (1999)

Studia Mathematica

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We prove trace inequalities of type | | u ' | | L 2 2 + j k j | u ( a j ) | 2 λ | | u | | L 2 2 where u H 1 ( ) , under suitable hypotheses on the sequences a j j and k j j , with the first sequence increasing and the second bounded.

Inequalities concerning polar derivative of polynomials

Arty Ahuja, K. K. Dewan, Sunil Hans (2011)

Annales Universitatis Mariae Curie-Sklodowska, sectio A – Mathematica

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In this paper we obtain certain results for the polar derivative of a polynomial p ( z ) = c n z n + j = μ n c n - j z n - j , 1 μ n , having all its zeros on | z | = k , k 1 , which generalizes the results due to Dewan and Mir, Dewan and Hans. We also obtain certain new inequalities concerning the maximum modulus of a polynomial with restricted zeros. [Editor’s note: There are flaws in the paper, see M. A. Qazi, Remarks on some recent results about polynomials with restricted zeros, Ann. Univ. Mariae Curie-Skłodowska Sect. A 67 (2), (2013),...

Absence of global solutions to a class of nonlinear parabolic inequalities

M. Guedda (2002)

Colloquium Mathematicae

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We study the absence of nonnegative global solutions to parabolic inequalities of the type u t - ( - Δ ) β / 2 u - V ( x ) u + h ( x , t ) u p , where ( - Δ ) β / 2 , 0 < β ≤ 2, is the β/2 fractional power of the Laplacian. We give a sufficient condition which implies that the only global solution is trivial if p > 1 is small. Among other properties, we derive a necessary condition for the existence of local and global nonnegative solutions to the above problem for the function V satisfying V ( x ) a | x | - b , where a ≥ 0, b > 0, p > 1 and V₊(x): = maxV(x),0....

Combinatorial inequalities and subspaces of L₁

Joscha Prochno, Carsten Schütt (2012)

Studia Mathematica

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Let M₁ and M₂ be N-functions. We establish some combinatorial inequalities and show that the product spaces M ( M ) are uniformly isomorphic to subspaces of L₁ if M₁ and M₂ are “separated” by a function t r , 1 < r < 2.

Convergence results for unbounded solutions of first order non-linear differential-functional equations

Henryk Leszczyński (1996)

Annales Polonici Mathematici

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We consider the Cauchy problem in an unbounded region for equations of the type either D t z ( t , x ) = f ( t , x , z ( t , x ) , z ( t , x ) , D x z ( t , x ) ) or D t z ( t , x ) = f ( t , x , z ( t , x ) , z , D x z ( t , x ) ) . We prove convergence of their difference analogues by means of recurrence inequalities in some wide classes of unbounded functions.

Geometry and inequalities of geometric mean

Trung Hoa Dinh, Sima Ahsani, Tin-Yau Tam (2016)

Czechoslovak Mathematical Journal

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We study some geometric properties associated with the t -geometric means A t B : = A 1 / 2 ( A - 1 / 2 B A - 1 / 2 ) t A 1 / 2 of two n × n positive definite matrices A and B . Some geodesical convexity results with respect to the Riemannian structure of the n × n positive definite matrices are obtained. Several norm inequalities with geometric mean are obtained. In particular, we generalize a recent result of Audenaert (2015). Numerical counterexamples are given for some inequality questions. A conjecture on the geometric mean inequality regarding...

Submultiplicative functions and operator inequalities

Hermann König, Vitali Milman (2014)

Studia Mathematica

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Let T: C¹(ℝ) → C(ℝ) be an operator satisfying the “chain rule inequality” T(f∘g) ≤ (Tf)∘g⋅Tg, f,g ∈ C¹(ℝ). Imposing a weak continuity and a non-degeneracy condition on T, we determine the form of all maps T satisfying this inequality together with T(-Id)(0) < 0. They have the form Tf = ⎧ ( H f / H ) f ' p , f’ ≥ 0, ⎨ ⎩ - A ( H f / H ) | f ' | p , f’ < 0, with p > 0, H ∈ C(ℝ), A ≥ 1. For A = 1, these are just the solutions of the chain rule operator equation. To prove this, we characterize the submultiplicative, measurable...