Sökning: "geometry and mathematical analysis Discrete mathematics"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden geometry and mathematical analysis Discrete mathematics.

1. 1. Vector-valued Eisenstein series of congruence types and their products

   Författare :Jiacheng Xia; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Hecke operator; Fourier expansion of modular forms; congruence type; products of Eisenstein series; vector-valued modular forms;

   Sammanfattning : Historically, Kohnen and Zagier connected modular forms with period polynomials, and as a consequence of this association concluded that the products of at most two Eisenstein series span all spaces of classical modular forms of level 1. Later Borisov and Gunnells among other authors extended the result to higher levels. LÄS MER

3. 2. Admissible transformations and the group classification of Schrödinger equations

   Författare :Celestin Kurujyibwami; Peter Basarab-Horwath; Roman Popovych; Pontelis Damianou; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : We study admissible transformations and solve group classification problems for various classes of linear and nonlinear Schrödinger equations with an arbitrary number n of space variables.The aim of the thesis is twofold. LÄS MER

4. 3. Stable High Order Finite Difference Methods for Wave Propagation and Flow Problems on Deforming Domains

   Författare :Samira Nikkar; Jan Nordström; Gunilla Kreiss; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : We construct stable, accurate and efficient numerical schemes for wave propagation and flow problems posed on spatial geometries that are moving, deforming, erroneously described or non-simply connected. The schemes are on Summation-by-Parts (SBP) form, combined with the Simultaneous Approximation Term (SAT) technique for imposing initial and boundary conditions. LÄS MER

5. 4. Automorphic forms and string theory: Small automorphic representations and non-perturbative effects

   Författare :Henrik Gustafsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; instantons; automorphic forms; automorphic representations; Eisenstein series; U-duality; non-perturbative effects; string theory;

   Sammanfattning : This compilation thesis stems from a project with the purpose of determining non-perturbative contributions to scattering amplitudes in string theory carrying important information about instantons, black hole quantum states and M-theory. The scattering amplitudes are functions on the moduli space invariant under the discrete U-duality group and this invariance is one of the defining properties of an automorphic form. LÄS MER

7. 5. Numerical methods for wave propagation in solids containing faults and fluid-filled fractures

   Författare :Ossian O'Reilly; Jan Nordström; Per Lötstedt; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This thesis develops numerical methods for the simulation of wave propagation in solids containing faults and fluid-filled fractures. These techniques have applications in earthquake hazard analysis, seismic imaging of reservoirs, and volcano seismology. A central component of this work is the coupling of mechanical systems. LÄS MER