Search for dissertations about: "boundedness"

Showing result 21 - 25 of 39 swedish dissertations containing the word boundedness.

  1. 21. Forever Young : Convolution Inequalities in Weighted Lorentz-type Spaces

    Author : Martin Křepela; Sorina Barza; Javier Soria; Karlstads universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Convolution; Young inequality; Lorentz spaces; weights; rearrangement-invariant spaces; Matematik; Mathematics;

    Abstract : This thesis is devoted to an investigation of boundedness of a general convolution operator between certain weighted Lorentz-type spaces with the aim of proving analogues of the Young convolution inequality for these spaces.Necessary and sufficient conditions on the kernel function are given, for which the convolution operator with the fixed kernel is bounded between a certain domain space and the weighted Lorentz space of type Gamma. READ MORE

  2. 22. Inequalities for some classes of Hardy type operators and compactness in weighted Lebesgue spaces

    Author : Akbota Abylayeva; Peter Wall; Lars-Erik Persson; Ryskul Oinarov; Luleå tekniska universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Abstract : This PhD thesis is devoted to investigate weighted differential Hardy inequalities and Hardy-type inequalities with the kernel when the kernel has an integrable singularity, and also the additivity of the estimate of a Hardy type operator with a kernel.The thesis consists of seven papers (Papers 1, 2, 3, 4, 5, 6, 7) and an introduction where a review on the subject of the thesis is given. READ MORE

  3. 23. On Feedforward Adaptation

    Author : Magnus Nilsson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; control; feedforward; adaptive;

    Abstract : Adaptation of a feedforward term in a two-degrees-of-freedom servo controller for single-input single-output systems is investigated in this thesis. The first part ofthe thesis gives a clarifying analysis of feedback-error learning in a linear and time-invariant framework. READ MORE

  4. 24. The Double Layer Potential Operator Through Functional Calculus

    Author : Michail Krimpogiannis; Andreas Rosén; Bengt-Ove Turesson; Kaj Nyström; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : Layer potential operators associated to elliptic partial differential equations have been an object of investigation for more than a century, due to their contribution in the solution of boundary value problems through integral equations.In this Licentiate thesis we prove the boundedness of the double layer potential operator on the Hilbert space of square integrable functions on the boundary, associated to second order uniformly elliptic equations in divergence form in the upper half-space, with real, possibly non-symmetric, bounded measurable coefficients, that do not depend on the variable transversal to the boundary. READ MORE

  5. 25. Reordering in Noncommutative Algebras, Orthogonal Polynomials and Operators

    Author : John Musonda; Sergei Silvestrov; Sten Kaijser; Johan Richter; Viktor Abramov; Mälardalens högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Mathematics Applied Mathematics; matematik tillämpad matematik;

    Abstract : The main object studied in this thesis is the multi-parametric family of unital associative complex algebras generated by the element $Q$ and the finite or infinite set $\{S_j\}_{j\in J}$ of elements satisfying the commutation relations $S_jQ=\sigma_j(Q)S_j$, where $\sigma_j$ is a polynomial for all $j\in J$. A concrete representation is given by the operators $Q_x(f)(x)=xf(x)$ and $\alpha_{\sigma_j}(f)(x)=f(\sigma_j(x))$ acting on polynomials or other suitable functions. READ MORE