Displaying similar documents to “Intersection properties for cones of monotone and convex functions with respect to the couple ( L p , B M O )

Specialization to the tangent cone and Whitney equisingularity

Arturo Giles Flores (2013)

Bulletin de la Société Mathématique de France

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Let ( X , 0 ) be a reduced, equidimensional germ of an analytic singularity with reduced tangent cone ( C X , 0 , 0 ) . We prove that the absence of exceptional cones is a necessary and sufficient condition for the smooth part 𝔛 0 of the specialization to the tangent cone ϕ : 𝔛 to satisfy Whitney’s conditions along the parameter axis Y . This result is a first step in generalizing to higher dimensions Lê and Teissier’s result for hypersurfaces of 3 which establishes the Whitney equisingularity of X and its tangent...

Interpolation of Cesàro sequence and function spaces

Sergey V. Astashkin, Lech Maligranda (2013)

Studia Mathematica

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The interpolation properties of Cesàro sequence and function spaces are investigated. It is shown that C e s p ( I ) is an interpolation space between C e s p ( I ) and C e s p ( I ) for 1 < p₀ < p₁ ≤ ∞ and 1/p = (1 - θ)/p₀ + θ/p₁ with 0 < θ < 1, where I = [0,∞) or [0,1]. The same result is true for Cesàro sequence spaces. On the other hand, C e s p [ 0 , 1 ] is not an interpolation space between Ces₁[0,1] and C e s [ 0 , 1 ] .

Interpolation of quasicontinuous functions

Joan Cerdà, Joaquim Martín, Pilar Silvestre (2011)

Banach Center Publications

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If C is a capacity on a measurable space, we prove that the restriction of the K-functional K ( t , f ; L p ( C ) , L ( C ) ) to quasicontinuous functions f ∈ QC is equivalent to K ( t , f ; L p ( C ) Q C , L ( C ) Q C ) . We apply this result to identify the interpolation space ( L p , q ( C ) Q C , L p , q ( C ) Q C ) θ , q .

The Lizorkin-Freitag formula for several weighted L p spaces and vector-valued interpolation

Irina Asekritova, Natan Krugljak, Ludmila Nikolova (2005)

Studia Mathematica

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A complete description of the real interpolation space L = ( L p ( ω ) , . . . , L p ( ω ) ) θ , q is given. An interesting feature of the result is that the whole measure space (Ω,μ) can be divided into disjoint pieces Ω i (i ∈ I) such that L is an l q sum of the restrictions of L to Ω i , and L on each Ω i is a result of interpolation of just two weighted L p spaces. The proof is based on a generalization of some recent results of the first two authors concerning real interpolation of vector-valued spaces.

On weak sharp minima for a special class of nonsmooth functions

Marcin Studniarski (2000)

Discussiones Mathematicae, Differential Inclusions, Control and Optimization

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We present a characterization of weak sharp local minimizers of order one for a function f: ℝⁿ → ℝ defined by f ( x ) : = m a x f i ( x ) | i = 1 , . . . , p , where the functions f i are strictly differentiable. It is given in terms of the gradients of f i and the Mordukhovich normal cone to a given set on which f is constant. Then we apply this result to a smooth nonlinear programming problem with constraints.

Complex interpolation of function spaces with general weights

Douadi Drihem (2023)

Commentationes Mathematicae Universitatis Carolinae

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We present the complex interpolation of Besov and Triebel–Lizorkin spaces with generalized smoothness. In some particular cases these function spaces are just weighted Besov and Triebel–Lizorkin spaces. As a corollary of our results, we obtain the complex interpolation between the weighted Triebel–Lizorkin spaces F ˙ p 0 , q 0 s 0 ( ω 0 ) and F ˙ , q 1 s 1 ( ω 1 ) with suitable assumptions on the parameters s 0 , s 1 , p 0 , q 0 and q 1 , and the pair of weights ( ω 0 , ω 1 ) .

On the positivity of semigroups of operators

Roland Lemmert, Peter Volkmann (1998)

Commentationes Mathematicae Universitatis Carolinae

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In a Banach space E , let U ( t ) ( t > 0 ) be a C 0 -semigroup with generating operator A . For a cone K E with non-empty interior we show: ( )     U ( t ) [ K ] K ( t > 0 ) holds if and only if A is quasimonotone increasing with respect to K . On the other hand, if A is not continuous, then there exists a regular cone K E such that A is quasimonotone increasing, but ( ) does not hold.

On linear maps leaving invariant the copositive/completely positive cones

Sachindranath Jayaraman, Vatsalkumar N. Mer (2024)

Czechoslovak Mathematical Journal

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The objective of this manuscript is to investigate the structure of linear maps on the space of real symmetric matrices 𝒮 n that leave invariant the closed convex cones of copositive and completely positive matrices ( COP n and CP n ). A description of an invertible linear map on 𝒮 n such that L ( CP n ) C P n is obtained in terms of semipositive maps over the positive semidefinite cone 𝒮 + n and the cone of symmetric nonnegative matrices 𝒩 + n for n 4 , with specific calculations for n = 2 . Preserver properties of the Lyapunov...

Modulus of dentability in L ¹ + L

Adam Bohonos, Ryszard Płuciennik (2008)

Banach Center Publications

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We introduce the notion of the modulus of dentability defined for any point of the unit sphere S(X) of a Banach space X. We calculate effectively this modulus for denting points of the unit ball of the classical interpolation space L ¹ + L . Moreover, a criterion for denting points of the unit ball in this space is given. We also show that none of denting points of the unit ball of L ¹ + L is a LUR-point. Consequently, the set of LUR-points of the unit ball of L ¹ + L is empty.

Real method of interpolation on subcouples of codimension one

S. V. Astashkin, P. Sunehag (2008)

Studia Mathematica

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We find necessary and sufficient conditions under which the norms of the interpolation spaces ( N , N ) θ , q and ( X , X ) θ , q are equivalent on N, where N is the kernel of a nonzero functional ψ ∈ (X₀ ∩ X₁)* and N i is the normed space N with the norm inherited from X i (i = 0,1). Our proof is based on reducing the problem to its partial case studied by Ivanov and Kalton, where ψ is bounded on one of the endpoint spaces. As an application we completely resolve the problem of when the range of the operator T θ = S - 2 θ I (S...

H functional calculus in real interpolation spaces

Giovanni Dore (1999)

Studia Mathematica

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Let A be a linear closed densely defined operator in a complex Banach space X. If A is of type ω (i.e. the spectrum of A is contained in a sector of angle 2ω, symmetric around the real positive axis, and λ ( λ I - A ) - 1 is bounded outside every larger sector) and has a bounded inverse, then A has a bounded H functional calculus in the real interpolation spaces between X and the domain of the operator itself.

H functional calculus in real interpolation spaces, II

Giovanni Dore (2001)

Studia Mathematica

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Let A be a linear closed one-to-one operator in a complex Banach space X, having dense domain and dense range. If A is of type ω (i.e.the spectrum of A is contained in a sector of angle 2ω, symmetric about the real positive axis, and | | λ ( λ I - A ) - 1 | | is bounded outside every larger sector), then A has a bounded H functional calculus in the real interpolation spaces between X and the intersection of the domain and the range of the operator itself.

Interpolation by elementary operators

Bojan Magajna (1993)

Studia Mathematica

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Given two n-tuples a = ( a 1 , . . . , a n ) and b = ( b 1 , . . . , b n ) of bounded linear operators on a Hilbert space the question of when there exists an elementary operator E such that E a j = b j for all j =1,...,n, is studied. The analogous question for left multiplications (instead of elementary operators) is answered in any C*-algebra A, as a consequence of the characterization of closed left A-submodules in A n .

Generalized Hardy spaces on tube domains over cones

Gustavo Garrigos (2001)

Colloquium Mathematicae

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We define a class of spaces H μ p , 0 < p < ∞, of holomorphic functions on the tube, with a norm of Hardy type: | | F | | H μ p p = s u p y Ω Ω ̅ | F ( x + i ( y + t ) ) | p d x d μ ( t ) . We allow μ to be any quasi-invariant measure with respect to a group acting simply transitively on the cone. We show the existence of boundary limits for functions in H μ p , and when p ≥ 1, characterize the boundary values as the functions in L μ p satisfying the tangential CR equations. A careful description of the measures μ when their supports lie on the boundary of the cone...

On some properties of generalized Marcinkiewicz spaces

Evgeniy Pustylnik (2001)

Studia Mathematica

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We give a full solution of the following problems concerning the spaces M φ ( X ) : (i) to what extent two functions φ and ψ should be different in order to ensure that M φ ( X ) M ψ ( X ) for any nontrivial Banach couple X⃗; (ii) when an embedding M φ ( X ) M ψ ( X ) can (or cannot) be dense; (iii) which Banach space can be regarded as an M φ ( X ) -space for some (unknown beforehand) Banach couple X⃗.

Interpolation and duality of generalized grand Morrey spaces on quasi-metric measure spaces

Yi Liu, Wen Yuan (2017)

Czechoslovak Mathematical Journal

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Let θ ( 0 , 1 ) , λ [ 0 , 1 ) and p , p 0 , p 1 ( 1 , ] be such that ( 1 - θ ) / p 0 + θ / p 1 = 1 / p , and let ϕ , ϕ 0 , ϕ 1 be some admissible functions such that ϕ , ϕ 0 p / p 0 and ϕ 1 p / p 1 are equivalent. We first prove that, via the ± interpolation method, the interpolation L ϕ 0 p 0 ) , λ ( 𝒳 ) , L ϕ 1 p 1 ) , λ ( 𝒳 ) , θ of two generalized grand Morrey spaces on a quasi-metric measure space 𝒳 is the generalized grand Morrey space L ϕ p ) , λ ( 𝒳 ) . Then, by using block functions, we also find a predual space of the generalized grand Morrey space. These results are new even for generalized grand Lebesgue spaces.

Structure of Cesàro function spaces: a survey

Sergey V. Astashkin, Lech Maligranda (2014)

Banach Center Publications

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Geometric structure of Cesàro function spaces C e s p ( I ) , where I = [0,1] and [0,∞), is investigated. Among other matters we present a description of their dual spaces, characterize the sets of all q ∈ [1,∞] such that C e s p [ 0 , 1 ] contains isomorphic and complemented copies of l q -spaces, show that Cesàro function spaces fail the fixed point property, give a description of subspaces generated by Rademacher functions in spaces C e s p [ 0 , 1 ] .