Sökning: "semigroups"

Visar resultat 11 - 15 av 17 avhandlingar innehållade ordet semigroups.

1. 11. On some topics in operator theory : An unfinished story about mathematical control

   Författare :Eskil Rydhe; Harmonic Analysis and Applications; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carleson embeddings; complex analysis; control theory; functional models; Hankel operators; harmonic analysis; operator theory; Triebel–Lizorkin spaces; vector-valued analytic functions;

   Sammanfattning : This thesis considers differentiation of non-negative, fractional order, composed with Hardy spacetypeHankel operators. H2-boundedness is characterized in terms of a reproducing kernel thesis. LÄS MER

3. 12. Structure and representations of bimodule categories

   Författare :Helena Jonsson; Volodymyr Mazorchuk; Pedro Vaz; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

   Sammanfattning : This thesis consists of four research papers in the field of representation theory. Three of the papers are concerned with bicategories of finite-dimensional bimodules over a family of radical square zero Nakayama algebras. In the first, we study the tensor combinatorics of these bimodules. LÄS MER

4. 13. On weak and strong convergence of numerical approximations of stochastic partial differential equations

   Författare :Fredrik Lindgren; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Additive noise; Cahn-Hilliard-Cook equation; Error estimate; Finite element; Hyperbolic equation; Parabolic equation; Rational approximation; Stochastic partial differential equation; Strong convergence; Truncation; Wiener process; Weak convergence; Weak convergence;

   Sammanfattning : This thesis is concerned with numerical approximation of linear stochastic partial differential equations driven by additive noise. In the first part, we develop a framework for the analysis of weak convergence and within this framework we analyze the stochastic heat equation, the stochastic wave equation, and the linearized stochastic Cahn-Hilliard, or the linearized Cahn-Hilliard-Cook equation. LÄS MER

5. 14. Weighted Bergman kernels and biharmonic Green functions

   Författare :Stefan Jakobsson; Matematikcentrum; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; singularity resolution of Bergman kernels; Hadamard s variational formula; weighted Bergman kernel; weighted biharmonic Green function; Friedrichs operator; Plant biochemistry; Växtbiokemi;

   Sammanfattning : The main theme of this thesis is the connection between weighted biharmonic Green functions and weighted Bergman kernels. In the first paper, which is a joint work with H. Hedenmalm and S. Shimorin, we prove that weighted biharmonic Green functions are positive for weights which satisfy a mean-value condition and whose logarithms are subharmonic. LÄS MER

7. 15. Finite element approximation of the deterministic and the stochastic Cahn-Hilliard equation

   Författare :Ali Mesforush; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite element; a priori error estimate; stochastic integral; mild solution; dual weighted residuals; a posteriori error estimate; additive noise; Wiener process; Cahn-Hilliard equation; existence; regularity; Lya- punov functional; stochastic convolution; Lya- punov functional;

   Sammanfattning : This thesis consists of three papers on numerical approximation of the Cahn-Hilliard equation. The main part of the work is concerned with the Cahn-Hilliard equation perturbed by noise, also known as the Cahn-Hilliard-Cook equation. LÄS MER