The Regularity of General Parabolic Systems with Degenerate Diffusion

The Regularity of General Parabolic Systems with Degenerate Diffusion PDF Author: Verena Bögelein
Publisher: American Mathematical Soc.
ISBN: 0821889753
Category : Mathematics
Languages : en
Pages : 155

Get Book Here

Book Description
The aim of the paper is twofold. On one hand the authors want to present a new technique called $p$-caloric approximation, which is a proper generalization of the classical compactness methods first developed by DeGiorgi with his Harmonic Approximation Lemma. This last result, initially introduced in the setting of Geometric Measure Theory to prove the regularity of minimal surfaces, is nowadays a classical tool to prove linearization and regularity results for vectorial problems. Here the authors develop a very far reaching version of this general principle devised to linearize general degenerate parabolic systems. The use of this result in turn allows the authors to achieve the subsequent and main aim of the paper, that is, the implementation of a partial regularity theory for parabolic systems with degenerate diffusion of the type $\partial_t u - \mathrm{div} a(Du)=0$, without necessarily assuming a quasi-diagonal structure, i.e. a structure prescribing that the gradient non-linearities depend only on the the explicit scalar quantity.

The Regularity of General Parabolic Systems with Degenerate Diffusion

The Regularity of General Parabolic Systems with Degenerate Diffusion PDF Author: Verena Bögelein
Publisher: American Mathematical Soc.
ISBN: 0821889753
Category : Mathematics
Languages : en
Pages : 155

Get Book Here

Book Description
The aim of the paper is twofold. On one hand the authors want to present a new technique called $p$-caloric approximation, which is a proper generalization of the classical compactness methods first developed by DeGiorgi with his Harmonic Approximation Lemma. This last result, initially introduced in the setting of Geometric Measure Theory to prove the regularity of minimal surfaces, is nowadays a classical tool to prove linearization and regularity results for vectorial problems. Here the authors develop a very far reaching version of this general principle devised to linearize general degenerate parabolic systems. The use of this result in turn allows the authors to achieve the subsequent and main aim of the paper, that is, the implementation of a partial regularity theory for parabolic systems with degenerate diffusion of the type $\partial_t u - \mathrm{div} a(Du)=0$, without necessarily assuming a quasi-diagonal structure, i.e. a structure prescribing that the gradient non-linearities depend only on the the explicit scalar quantity.

On the Regularity of the Composition of Diffeomorphisms

On the Regularity of the Composition of Diffeomorphisms PDF Author: H. Inci
Publisher: American Mathematical Soc.
ISBN: 0821887416
Category : Mathematics
Languages : en
Pages : 72

Get Book Here

Book Description
For M a closed manifold or the Euclidean space Rn we present a detailed proof of regularity properties of the composition of Hs-regular diffeomorphisms of M for s > 12dim⁡M+1.

Global Regularity for the Yang-Mills Equations on High Dimensional Minkowski Space

Global Regularity for the Yang-Mills Equations on High Dimensional Minkowski Space PDF Author: Joachim Krieger
Publisher: American Mathematical Soc.
ISBN: 082184489X
Category : Mathematics
Languages : en
Pages : 111

Get Book Here

Book Description
This monograph contains a study of the global Cauchy problem for the Yang-Mills equations on $(6+1)$ and higher dimensional Minkowski space, when the initial data sets are small in the critical gauge covariant Sobolev space $\dot{H}_A^{(n-4)/{2}}$. Regularity is obtained through a certain ``microlocal geometric renormalization'' of the equations which is implemented via a family of approximate null Cronstrom gauge transformations. The argument is then reduced to controlling some degenerate elliptic equations in high index and non-isotropic $L^p$ spaces, and also proving some bilinear estimates in specially constructed square-function spaces.

Contemporary Research in Elliptic PDEs and Related Topics

Contemporary Research in Elliptic PDEs and Related Topics PDF Author: Serena Dipierro
Publisher: Springer
ISBN: 303018921X
Category : Mathematics
Languages : en
Pages : 502

Get Book Here

Book Description
This volume collects contributions from the speakers at an INdAM Intensive period held at the University of Bari in 2017. The contributions cover several aspects of partial differential equations whose development in recent years has experienced major breakthroughs in terms of both theory and applications. The topics covered include nonlocal equations, elliptic equations and systems, fully nonlinear equations, nonlinear parabolic equations, overdetermined boundary value problems, maximum principles, geometric analysis, control theory, mean field games, and bio-mathematics. The authors are trailblazers in these topics and present their work in a way that is exhaustive and clearly accessible to PhD students and early career researcher. As such, the book offers an excellent introduction to a variety of fundamental topics of contemporary investigation and inspires novel and high-quality research.

Strange Attractors for Periodically Forced Parabolic Equations

Strange Attractors for Periodically Forced Parabolic Equations PDF Author: Kening Lu
Publisher: American Mathematical Soc.
ISBN: 0821884840
Category : Mathematics
Languages : en
Pages : 97

Get Book Here

Book Description
The authors prove that in systems undergoing Hopf bifurcations, the effects of periodic forcing can be amplified by the shearing in the system to create sustained chaotic behavior. Specifically, strange attractors with SRB measures are shown to exist. The analysis is carried out for infinite dimensional systems, and the results are applicable to partial differential equations. Application of the general results to a concrete equation, namely the Brusselator, is given.

On the Steady Motion of a Coupled System Solid-Liquid

On the Steady Motion of a Coupled System Solid-Liquid PDF Author: Josef Bemelmans
Publisher: American Mathematical Soc.
ISBN: 0821887734
Category : Mathematics
Languages : en
Pages : 102

Get Book Here

Book Description
We study the unconstrained (free) motion of an elastic solid B in a Navier-Stokes liquid L occupying the whole space outside B, under the assumption that a constant body force b is acting on B. More specifically, we are interested in the steady motion of the coupled system {B,L}, which means that there exists a frame with respect to which the relevant governing equations possess a time-independent solution. We prove the existence of such a frame, provided some smallness restrictions are imposed on the physical parameters, and the reference configuration of B satisfies suitable geometric properties.

Non-cooperative Equilibria of Fermi Systems with Long Range Interactions

Non-cooperative Equilibria of Fermi Systems with Long Range Interactions PDF Author: Jean-Bernard Bru
Publisher: American Mathematical Soc.
ISBN: 0821889761
Category : Mathematics
Languages : en
Pages : 173

Get Book Here

Book Description
The authors define a Banach space $\mathcal{M}_{1}$ of models for fermions or quantum spins in the lattice with long range interactions and make explicit the structure of (generalized) equilibrium states for any $\mathfrak{m}\in \mathcal{M}_{1}$. In particular, the authors give a first answer to an old open problem in mathematical physics--first addressed by Ginibre in 1968 within a different context--about the validity of the so-called Bogoliubov approximation on the level of states. Depending on the model $\mathfrak{m}\in \mathcal{M}_{1}$, the authors' method provides a systematic way to study all its correlation functions at equilibrium and can thus be used to analyze the physics of long range interactions. Furthermore, the authors show that the thermodynamics of long range models $\mathfrak{m}\in \mathcal{M}_{1}$ is governed by the non-cooperative equilibria of a zero-sum game, called here thermodynamic game.

Weighted Bergman Spaces Induced by Rapidly Increasing Weights

Weighted Bergman Spaces Induced by Rapidly Increasing Weights PDF Author: Jose Angel Pelaez
Publisher: American Mathematical Soc.
ISBN: 0821888021
Category : Mathematics
Languages : en
Pages : 136

Get Book Here

Book Description
This monograph is devoted to the study of the weighted Bergman space $A^p_\omega$ of the unit disc $\mathbb{D}$ that is induced by a radial continuous weight $\omega$ satisfying $\lim_{r\to 1^-}\frac{\int_r^1\omega(s)\,ds}{\omega(r)(1-r)}=\infty.$ Every such $A^p_\omega$ lies between the Hardy space $H^p$ and every classical weighted Bergman space $A^p_\alpha$. Even if it is well known that $H^p$ is the limit of $A^p_\alpha$, as $\alpha\to-1$, in many respects, it is shown that $A^p_\omega$ lies ``closer'' to $H^p$ than any $A^p_\alpha$, and that several finer function-theoretic properties of $A^p_\alpha$ do not carry over to $A^p_\omega$.

Relative Equilibria in the 3-Dimensional Curved $n$-Body Problem

Relative Equilibria in the 3-Dimensional Curved $n$-Body Problem PDF Author: Florin Diacu
Publisher: American Mathematical Soc.
ISBN: 0821891367
Category : Mathematics
Languages : en
Pages : 92

Get Book Here

Book Description
Considers the 3 -dimensional gravitational n -body problem, n32 , in spaces of constant Gaussian curvature k10 , i.e. on spheres S 3 ?1 , for ?>0 , and on hyperbolic manifolds H 3 ?1, for ?

Nonlinear Stability of Ekman Boundary Layers in Rotating Stratified Fluids

Nonlinear Stability of Ekman Boundary Layers in Rotating Stratified Fluids PDF Author: Hajime Koba
Publisher: American Mathematical Soc.
ISBN: 0821891332
Category : Mathematics
Languages : en
Pages : 142

Get Book Here

Book Description
A stationary solution of the rotating Navier-Stokes equations with a boundary condition is called an Ekman boundary layer. This book constructs stationary solutions of the rotating Navier-Stokes-Boussinesq equations with stratification effects in the case when the rotating axis is not necessarily perpendicular to the horizon. The author calls such stationary solutions Ekman layers. This book shows the existence of a weak solution to an Ekman perturbed system, which satisfies the strong energy inequality. Moreover, the author discusses the uniqueness of weak solutions and computes the decay rate of weak solutions with respect to time under some assumptions on the Ekman layers and the physical parameters. The author also shows that there exists a unique global-in-time strong solution of the perturbed system when the initial datum is sufficiently small. Comparing a weak solution satisfying the strong energy inequality with the strong solution implies that the weak solution is smooth with respect to time when time is sufficiently large.