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Displaying 61 – 80 of 91

Constructing a relativistic heat flow by transport time steps

Robert J. McCann, Marjolaine Puel (2009)

Annales de l'I.H.P. Analyse non linéaire

Construction of Dilations of Positive Lp-Contractions.

Mustafa A. Akcoglu, P. Ekkehard Kopp (1977)

Mathematische Zeitschrift

Continuity of Pseudo-differential Operators on Bessel And Besov Spaces

Moussai, Madani (2001)

Serdica Mathematical Journal

We study the continuity of pseudo-differential operators on Bessel potential spaces Hs|p (Rn ), and on the corresponding Besov spaces B^(s,q)p (R ^n). The modulus of continuity ω we use is assumed to satisfy j≥0, ∑ [ω(2−j )Ω(2j )]2 < ∞ where Ω is a suitable positive function.

Continuity of superposition operators on $w_{0}$ and $W_{0}$

Ryszard Płuciennik (1990)

Commentationes Mathematicae Universitatis Carolinae

Continuous and compact imbeddings of weighted Sobolev spaces. I

Petr Gurka, Bohumír Opic (1988)

Czechoslovak Mathematical Journal

Continuous selections for a class of non-convex multivalued maps

Andrzej Fryszkowski (1983)

Studia Mathematica

Contre-exemples associés aux théorèmes de Rosenthal. Quelques propriétés liées à ces résultats

Gilles Godefroy (1975/1976)

Séminaire Choquet. Initiation à l'analyse

Convergence of greedy approximation II. The trigonometric system

S. V. Konyagin, V. N. Temlyakov (2003)

Studia Mathematica

We study the following nonlinear method of approximation by trigonometric polynomials. For a periodic function f we take as an approximant a trigonometric polynomial of the form $G ₘ (f) : = \sum_{k \in Λ} f ̂ (k) e^{i (k, x)}$ , where $Λ \subset ℤ^{d}$ is a set of cardinality m containing the indices of the m largest (in absolute value) Fourier coefficients f̂(k) of the function f. Note that Gₘ(f) gives the best m-term approximant in the L₂-norm, and therefore, for each f ∈ L₂, ||f-Gₘ(f)||₂ → 0 as m → ∞. It is known from previous results that in the case of...

Convergence of orthogonal series of projections in Banach spaces

Ryszard Jajte, Adam Paszkiewicz (1997)

Annales Polonici Mathematici

For a sequence $(A_{j})$ of mutually orthogonal projections in a Banach space, we discuss all possible limits of the sums $S_{n} = \sum_{j = 1}^{n} A_{j}$ in a “strong” sense. Those limits turn out to be some special idempotent operators (unbounded, in general). In the case of X = L₂(Ω,μ), an arbitrary unbounded closed and densely defined operator A in X may be the μ-almost sure limit of $S_{n}$ (i.e. $S_{n} f \to A f$ μ-a.e. for all f ∈ (A)).

Convergence of Taylor series in Hardy and Besov spaces.

Liliana Gabriela Gheorghe (2001)

Extracta Mathematicae

Convergences de séries dans les espaces d'Orlicz

P. Turpin (1973/1974)

Séminaire Analyse fonctionnelle (dit "Maurey-Schwartz")

Convex Functions on Dual Systems.

Helmut Strasser (1975)

Mathematische Annalen

Convex-like inequality, homogeneity, subadditivity, and a characterization of $L^{p}$ -norm

Janusz Matkowski, Marek Pycia (1995)

Annales Polonici Mathematici

Let a and b be fixed real numbers such that 0 < mina,b < 1 < a + b. We prove that every function f:(0,∞) → ℝ satisfying f(as + bt) ≤ af(s) + bf(t), s,t > 0, and such that $l i m s u p_{t \to 0 +} f (t) \leq 0$ must be of the form f(t) = f(1)t, t > 0. This improves an earlier result in [5] where, in particular, f is assumed to be nonnegative. Some generalizations for functions defined on cones in linear spaces are given. We apply these results to give a new characterization of the $L^{p}$ -norm.

Convolution algebras with weighted rearrangement-invariant norm

R. Kerman, E. Sawyer (1994)

Studia Mathematica

Let X be a rearrangement-invariant space of Lebesgue-measurable functions on $ℝ^{n}$ , such as the classical Lebesgue, Lorentz or Orlicz spaces. Given a nonnegative, measurable (weight) function on $ℝ^{n}$ , define $X (w) = F : ℝ^{n} \to ℂ : \infty > ∥ F ∥_{X (w)} : = ∥ F w ∥_{X}$ . We investigate conditions on such a weight w that guarantee X(w) is an algebra under the convolution product F∗G defined at $x \in ℝ^{n}$ by $(F * G) (x) = ʃ_{ℝ^{n}} F (x - y) G (y) d y$ ; more precisely, when $∥ F * G ∥_{X (w)} \leq ∥ F ∥_{X (w)} ∥ G ∥_{X (w)}$ for all F,G ∈ X(w).

Convolutions of Vector Fields-I.

M.M. Rao (1980)

Mathematische Zeitschrift

Coorbit space theory for quasi-Banach spaces

Holger Rauhut (2007)

Studia Mathematica

We generalize the classical coorbit space theory developed by Feichtinger and Gröchenig to quasi-Banach spaces. As a main result we provide atomic decompositions for coorbit spaces defined with respect to quasi-Banach spaces. These atomic decompositions are used to prove fast convergence rates of best n-term approximation schemes. We apply the abstract theory to time-frequency analysis of modulation spaces $M_{m}^{p, q}$ , 0 < p,q ≤ ∞.

Copies of C0 in Certain Vector-Valued Function Banach Spaces.

J.C. Ferrando (1995)

Mathematica Scandinavica

Copies of $l^{1}$ and $c_{o}$ in Musielak-Orlicz sequence spaces

Ghassan Alherk, Henryk Hudzik (1994)

Commentationes Mathematicae Universitatis Carolinae

Criteria in order that a Musielak-Orlicz sequence space $l^{Φ}$ contains an isomorphic as well as an isomorphically isometric copy of $l^{1}$ are given. Moreover, it is proved that if $Φ = (Φ_{i})$ , where $Φ_{i}$ are defined on a Banach space, $X$ does not satisfy the $δ_{2}^{o}$ -condition, then the Musielak-Orlicz sequence space $l^{Φ} (X)$ of $X$ -valued sequences contains an almost isometric copy of $c_{o}$ . In the case of $X = I R$ it is proved also that if $l^{Φ}$ contains an isomorphic copy of $c_{o}$ , then $Φ$ does not satisfy the $δ_{2}^{o}$ -condition. These results extend some...

Copies of Orlicz sequences spaces in the interpolation spaces ${\bar{A}}_{ρ, Φ}$ .

Echandía, Ventura, Hernández, Jorge (2008)

Divulgaciones Matemáticas

Correction to the paper “On weighted $H^{p}$ spaces” (Studia Math. 40 (1971), pp. 109-159)

T. Walsh (1972)

Studia Mathematica

Currently displaying 61 – 80 of 91

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