Semigroup Approach To Nonlinear Diffusion Equations

Semigroup Approach To Nonlinear Diffusion Equations

Author: Viorel Barbu

Publisher: World Scientific

Published: 2021-09-23

Total Pages: 221

ISBN-13: 981124653X

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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

Author: Gabriela Marinoschi

Publisher: Springer Nature

Published: 2023-03-28

Total Pages: 223

ISBN-13: 3031245830

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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 Differential Equations of Monotone Types in Banach Spaces

Nonlinear Differential Equations of Monotone Types in Banach Spaces

Author: Viorel Barbu

Publisher: Springer Science & Business Media

Published: 2010-01-01

Total Pages: 283

ISBN-13: 1441955429

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This monograph is concerned with the basic results on Cauchy problems associated with nonlinear monotone operators in Banach spaces with applications to partial differential equations of evolutive type. It focuses on major results in recent decades.


Degenerate Nonlinear Diffusion Equations

Degenerate Nonlinear Diffusion Equations

Author: Angelo Favini

Publisher: Springer

Published: 2012-05-08

Total Pages: 165

ISBN-13: 3642282857

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The aim of these notes is to include in a uniform presentation style several topics related to the theory of degenerate nonlinear diffusion equations, treated in the mathematical framework of evolution equations with multivalued m-accretive operators in Hilbert spaces. The problems concern nonlinear parabolic equations involving two cases of degeneracy. More precisely, one case is due to the vanishing of the time derivative coefficient and the other is provided by the vanishing of the diffusion coefficient on subsets of positive measure of the domain. From the mathematical point of view the results presented in these notes can be considered as general results in the theory of degenerate nonlinear diffusion equations. However, this work does not seek to present an exhaustive study of degenerate diffusion equations, but rather to emphasize some rigorous and efficient techniques for approaching various problems involving degenerate nonlinear diffusion equations, such as well-posedness, periodic solutions, asymptotic behaviour, discretization schemes, coefficient identification, and to introduce relevant solving methods for each of them.


Nonlinear Diffusion Equations and Their Equilibrium States, 3

Nonlinear Diffusion Equations and Their Equilibrium States, 3

Author: N.G Lloyd

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 567

ISBN-13: 1461203937

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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 Curvature Conditions in Metric Measure Spaces

Nonlinear Diffusion Equations and Curvature Conditions in Metric Measure Spaces

Author: Luigi Ambrosio

Publisher: American Mathematical Soc.

Published: 2020-02-13

Total Pages: 134

ISBN-13: 1470439131

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The 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, the authors' 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, the authors' 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.


Semigroup Methods for Evolution Equations on Networks

Semigroup Methods for Evolution Equations on Networks

Author: Delio Mugnolo

Publisher: Springer

Published: 2014-05-21

Total Pages: 294

ISBN-13: 3319046217

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This concise text is based on a series of lectures held only a few years ago and originally intended as an introduction to known results on linear hyperbolic and parabolic equations. Yet the topic of differential equations on graphs, ramified spaces, and more general network-like objects has recently gained significant momentum and, well beyond the confines of mathematics, there is a lively interdisciplinary discourse on all aspects of so-called complex networks. Such network-like structures can be found in virtually all branches of science, engineering and the humanities, and future research thus calls for solid theoretical foundations. This book is specifically devoted to the study of evolution equations – i.e., of time-dependent differential equations such as the heat equation, the wave equation, or the Schrödinger equation (quantum graphs) – bearing in mind that the majority of the literature in the last ten years on the subject of differential equations of graphs has been devoted to elliptic equations and related spectral problems. Moreover, for tackling the most general settings - e.g. encoded in the transmission conditions in the network nodes - one classical and elegant tool is that of operator semigroups. This book is simultaneously a very concise introduction to this theory and a handbook on its applications to differential equations on networks. With a more interdisciplinary readership in mind, full proofs of mathematical statements have been frequently omitted in favor of keeping the text as concise, fluid and self-contained as possible. In addition, a brief chapter devoted to the field of neurodynamics of the brain cortex provides a concrete link to ongoing applied research.


Smoothing and Decay Estimates for Nonlinear Diffusion Equations

Smoothing and Decay Estimates for Nonlinear Diffusion Equations

Author: Juan Luis Vázquez

Publisher: Oxford University Press, USA

Published: 2006-08-03

Total Pages: 249

ISBN-13: 0199202974

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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.


Lecture Notes In Applied Differential Equations Of Mathematical Physics

Lecture Notes In Applied Differential Equations Of Mathematical Physics

Author: Luiz C L Botelho

Publisher: World Scientific

Published: 2008-09-10

Total Pages: 340

ISBN-13: 981447102X

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Functional analysis is a well-established powerful method in mathematical physics, especially those mathematical methods used in modern non-perturbative quantum field theory and statistical turbulence. This book presents a unique, modern treatment of solutions to fractional random differential equations in mathematical physics. It follows an analytic approach in applied functional analysis for functional integration in quantum physics and stochastic Langevin-turbulent partial differential equations.


Theory and Applications of Partial Functional Differential Equations

Theory and Applications of Partial Functional Differential Equations

Author: Jianhong Wu

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 441

ISBN-13: 1461240506

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Abstract semilinear functional differential equations arise from many biological, chemical, and physical systems which are characterized by both spatial and temporal variables and exhibit various spatio-temporal patterns. The aim of this book is to provide an introduction of the qualitative theory and applications of these equations from the dynamical systems point of view. The required prerequisites for that book are at a level of a graduate student. The style of presentation will be appealing to people trained and interested in qualitative theory of ordinary and functional differential equations.