Semigroup Approach To Nonlinear Diffusion Equations

Semigroup Approach To Nonlinear Diffusion Equations PDF Author: Viorel Barbu
Publisher: World Scientific
ISBN: 981124653X
Category : Mathematics
Languages : en
Pages : 221

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Book Description
This book is concerned with functional methods (nonlinear semigroups of contractions, nonlinear m-accretive operators and variational techniques) in the theory of nonlinear partial differential equations of elliptic and parabolic type. In particular, applications to the existence theory of nonlinear parabolic equations, nonlinear Fokker-Planck equations, phase transition and free boundary problems are presented in details. Emphasis is put on functional methods in partial differential equations (PDE) and less on specific results.

Semigroup Approach To Nonlinear Diffusion Equations

Semigroup Approach To Nonlinear Diffusion Equations PDF Author: Viorel Barbu
Publisher: World Scientific
ISBN: 981124653X
Category : Mathematics
Languages : en
Pages : 221

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Book Description
This book is concerned with functional methods (nonlinear semigroups of contractions, nonlinear m-accretive operators and variational techniques) in the theory of nonlinear partial differential equations of elliptic and parabolic type. In particular, applications to the existence theory of nonlinear parabolic equations, nonlinear Fokker-Planck equations, phase transition and free boundary problems are presented in details. Emphasis is put on functional methods in partial differential equations (PDE) and less on specific results.

Dual Variational Approach to Nonlinear Diffusion Equations

Dual Variational Approach to Nonlinear Diffusion Equations PDF Author: Gabriela Marinoschi
Publisher: Springer Nature
ISBN: 3031245830
Category : Mathematics
Languages : en
Pages : 223

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Book Description
This monograph explores a dual variational formulation of solutions to nonlinear diffusion equations with general nonlinearities as null minimizers of appropriate energy functionals. The author demonstrates how this method can be utilized as a convenient tool for proving the existence of these solutions when others may fail, such as in cases of evolution equations with nonautonomous operators, with low regular data, or with singular diffusion coefficients. By reducing it to a minimization problem, the original problem is transformed into an optimal control problem with a linear state equation. This procedure simplifies the proof of the existence of minimizers and, in particular, the determination of the first-order conditions of optimality. The dual variational formulation is illustrated in the text with specific diffusion equations that have general nonlinearities provided by potentials having various stronger or weaker properties. These equations can represent mathematical models to various real-world physical processes. Inverse problems and optimal control problems are also considered, as this technique is useful in their treatment as well.

Nonlinear Semigroups, Partial Differential Equations and Attractors

Nonlinear Semigroups, Partial Differential Equations and Attractors PDF Author: T.L. Gill
Publisher: Springer
ISBN: 3540477918
Category : Mathematics
Languages : en
Pages : 194

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Book Description
The original idea of the organizers of the Washington Symposium was to span a fairly narrow range of topics on some recent techniques developed for the investigation of nonlinear partial differential equations and discuss these in a forum of experts. It soon became clear, however, that the dynamical systems approach interfaced significantly with many important branches of applied mathematics. As a consequence, the scope of this resulting proceedings volume is an enlarged one with coverage of a wider range of research topics.

Nonlinear Diffusion Equations

Nonlinear Diffusion Equations PDF Author: Zhuoqun Wu
Publisher: World Scientific
ISBN: 9810247184
Category : Mathematics
Languages : en
Pages : 521

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Book Description
Nonlinear diffusion equations, an important class of parabolic equations, come from a variety of diffusion phenomena which appear widely in nature. They are suggested as mathematical models of physical problems in many fields, such as filtration, phase transition, biochemistry and dynamics of biological groups. In many cases, the equations possess degeneracy or singularity. The appearance of degeneracy or singularity makes the study more involved and challenging. Many new ideas and methods have been developed to overcome the special difficulties caused by the degeneracy and singularity, which enrich the theory of partial differential equations.This book provides a comprehensive presentation of the basic problems, main results and typical methods for nonlinear diffusion equations with degeneracy. Some results for equations with singularity are touched upon.

Smoothing and Decay Estimates for Nonlinear Diffusion Equations

Smoothing and Decay Estimates for Nonlinear Diffusion Equations PDF Author: Juan Luis Vázquez
Publisher: Oxford University Press, USA
ISBN: 0199202974
Category : Mathematics
Languages : en
Pages : 249

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Book Description
This text is concerned with quantitative aspects of the theory of nonlinear diffusion equations, whichappear as mathematical models in different branches of Physics, Chemistry, Biology and Engineering.

Nonlinear Diffusion

Nonlinear Diffusion PDF Author: Homer Franklin Walker
Publisher: Pitman Publishing
ISBN:
Category : Mathematics
Languages : en
Pages : 246

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Book Description


Nonlinear Diffusion Equations and Curvature Conditions in Metric Measure Spaces

Nonlinear Diffusion Equations and Curvature Conditions in Metric Measure Spaces PDF Author: Luigi Ambrosio
Publisher:
ISBN: 9781470455149
Category : Differential calculus
Languages : en
Pages : 121

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Book Description
Aim of this paper is to provide new characterizations of the curvature dimension condition in the context of metric measure spaces (X, d, m). On the geometric side, our new approach takes into account suitable weighted action functionals which provide the natural modulus of K-convexity when one investigates the convexity properties of N-dimensional entropies. On the side of diffusion semigroups and evolution variational inequalities, our new approach uses the nonlinear diffusion semigroup induced by the N-dimensional entropy, in place of the heat flow. Under suitable assumptions (most notably the quadraticity of Cheeger's energy relative to the metric measure structure) both approaches are shown to be equivalent to the strong CD*(K, N) condition of Bacher-Sturm.

Nonlinear Diffusion Equations and Their Equilibrium States, 3

Nonlinear Diffusion Equations and Their Equilibrium States, 3 PDF Author: N.G Lloyd
Publisher: Springer Science & Business Media
ISBN: 1461203937
Category : Mathematics
Languages : en
Pages : 567

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Book Description
Nonlinear diffusion equations have held a prominent place in the theory of partial differential equations, both for the challenging and deep math ematical questions posed by such equations and the important role they play in many areas of science and technology. Examples of current inter est are biological and chemical pattern formation, semiconductor design, environmental problems such as solute transport in groundwater flow, phase transitions and combustion theory. Central to the theory is the equation Ut = ~cp(U) + f(u). Here ~ denotes the n-dimensional Laplacian, cp and f are given functions and the solution is defined on some domain n x [0, T] in space-time. FUn damental questions concern the existence, uniqueness and regularity of so lutions, the existence of interfaces or free boundaries, the question as to whether or not the solution can be continued for all time, the asymptotic behavior, both in time and space, and the development of singularities, for instance when the solution ceases to exist after finite time, either through extinction or through blow up.

Nonlinear Diffusion Equations and Their Equilibrium States I

Nonlinear Diffusion Equations and Their Equilibrium States I PDF Author: W.-M. Ni
Publisher: Springer Science & Business Media
ISBN: 1461396050
Category : Mathematics
Languages : en
Pages : 359

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Book Description
In recent years considerable interest has been focused on nonlinear diffu sion problems, the archetypical equation for these being Ut = D.u + f(u). Here D. denotes the n-dimensional Laplacian, the solution u = u(x, t) is defined over some space-time domain of the form n x [O,T], and f(u) is a given real function whose form is determined by various physical and mathematical applications. These applications have become more varied and widespread as problem after problem has been shown to lead to an equation of this type or to its time-independent counterpart, the elliptic equation of equilibrium D.u + f(u) = o. Particular cases arise, for example, in population genetics, the physics of nu clear stability, phase transitions between liquids and gases, flows in porous media, the Lend-Emden equation of astrophysics, various simplified com bustion models, and in determining metrics which realize given scalar or Gaussian curvatures. In the latter direction, for example, the problem of finding conformal metrics with prescribed curvature leads to a ground state problem involving critical exponents. Thus not only analysts, but geome ters as well, can find common ground in the present work. The corresponding mathematical problem is to determine how the struc ture of the nonlinear function f(u) influences the behavior of the solution.

Nonlinear Diffusion Equations and Their Equilibrium States II

Nonlinear Diffusion Equations and Their Equilibrium States II PDF Author: W.-M. Ni
Publisher: Springer Science & Business Media
ISBN: 1461396085
Category : Mathematics
Languages : en
Pages : 364

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Book Description
In recent years considerable interest has been focused on nonlinear diffu sion problems, the archetypical equation for these being Ut = ~U + f(u). Here ~ denotes the n-dimensional Laplacian, the solution u = u(x, t) is defined over some space-time domain of the form n x [O,T], and f(u) is a given real function whose form is determined by various physical and mathematical applications. These applications have become more varied and widespread as problem after problem has been shown to lead to an equation of this type or to its time-independent counterpart, the elliptic equation of equilibrium ~u+f(u)=O. Particular cases arise, for example, in population genetics, the physics of nu clear stability, phase transitions between liquids and gases, flows in porous media, the Lend-Emden equation of astrophysics, various simplified com bustion models, and in determining metrics which realize given scalar or Gaussian curvatures. In the latter direction, for example, the problem of finding conformal metrics with prescribed curvature leads to a ground state problem involving critical exponents. Thus not only analysts, but geome ters as well, can find common ground in the present work. The corresponding mathematical problem is to determine how the struc ture of the nonlinear function f(u) influences the behavior of the solution.