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Book
An Introduction to the Regularity Theory for Elliptic Systems, Harmonic Maps and Minimal Graphs
Authors: ---
ISBN: 8876424423 8876424431 Year: 2012 Publisher: Pisa : Scuola Normale Superiore : Imprint: Edizioni della Normale,

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This volume deals with the regularity theory for elliptic systems. We may find the origin of such a theory in two of the problems posed by David Hilbert in his celebrated lecture delivered during the International Congress of Mathematicians in 1900 in Paris: 19th problem: Are the solutions to regular problems in the Calculus of Variations always necessarily analytic? 20th problem: does any variational problem have a solution, provided that certain assumptions regarding the given boundary conditions are satisfied, and provided that the notion of a solution is suitably extended? During the last century these two problems have generated a great deal of work, usually referred to as regularity theory, which makes this topic quite relevant in many fields and still very active for research. However, the purpose of this volume, addressed mainly to students, is much more limited. We aim to illustrate only some of the basic ideas and techniques introduced in this context, confining ourselves to important but simple situations and refraining from completeness. In fact some relevant topics are omitted. Topics include: harmonic functions, direct methods, Hilbert space methods and Sobolev spaces, energy estimates, Schauder and Lp-theory both with and without potential theory, including the Calderon-Zygmund theorem, Harnack's and De Giorgi-Moser-Nash theorems in the scalar case and partial regularity theorems in the vector valued case; energy minimizing harmonic maps and minimal graphs in codimension 1 and greater than 1. In this second deeply revised edition we also included the regularity of 2-dimensional weakly harmonic maps, the partial regularity of stationary harmonic maps, and their connections with the case p=1 of the Lp theory, including the celebrated results of Wente and of Coifman-Lions-Meyer-Semmes.


Book
Microlocal and Time-Frequency Analysis
Authors: ---
Year: 2022 Publisher: Basel MDPI - Multidisciplinary Digital Publishing Institute


Book
Microlocal and Time-Frequency Analysis
Authors: ---
Year: 2022 Publisher: Basel MDPI - Multidisciplinary Digital Publishing Institute


Book
Hölder Continuous Euler Flows in Three Dimensions with Compact Support in Time
Author:
ISBN: 1400885426 Year: 2017 Publisher: Princeton, NJ : Princeton University Press,

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Motivated by the theory of turbulence in fluids, the physicist and chemist Lars Onsager conjectured in 1949 that weak solutions to the incompressible Euler equations might fail to conserve energy if their spatial regularity was below 1/3-Hölder. In this book, Philip Isett uses the method of convex integration to achieve the best-known results regarding nonuniqueness of solutions and Onsager's conjecture. Focusing on the intuition behind the method, the ideas introduced now play a pivotal role in the ongoing study of weak solutions to fluid dynamics equations.The construction itself-an intricate algorithm with hidden symmetries-mixes together transport equations, algebra, the method of nonstationary phase, underdetermined partial differential equations (PDEs), and specially designed high-frequency waves built using nonlinear phase functions. The powerful "Main Lemma"-used here to construct nonzero solutions with compact support in time and to prove nonuniqueness of solutions to the initial value problem-has been extended to a broad range of applications that are surveyed in the appendix. Appropriate for students and researchers studying nonlinear PDEs, this book aims to be as robust as possible and pinpoints the main difficulties that presently stand in the way of a full solution to Onsager's conjecture.

Keywords

Fluid dynamics --- Mathematics. --- Beltrami flows. --- Einstein summation convention. --- Euler equations. --- Euler flow. --- Euler-Reynolds equations. --- Euler-Reynolds system. --- Galilean invariance. --- Galilean transformation. --- HighЈigh Interference term. --- HighЈigh term. --- HighЌow Interaction term. --- Hlder norm. --- Hlder regularity. --- Lars Onsager. --- Main Lemma. --- Main Theorem. --- Mollification term. --- Newton's law. --- Noether's theorem. --- Onsager's conjecture. --- Reynolds stres. --- Reynolds stress. --- Stress equation. --- Stress term. --- Transport equation. --- Transport term. --- Transport-Elliptic equation. --- abstract index notation. --- algebra. --- amplitude. --- coarse scale flow. --- coarse scale velocity. --- coefficient. --- commutator estimate. --- commutator term. --- commutator. --- conservation of momentum. --- continuous solution. --- contravariant tensor. --- convergence. --- convex integration. --- correction term. --- correction. --- covariant tensor. --- dimensional analysis. --- divergence equation. --- divergence free vector field. --- divergence operator. --- energy approximation. --- energy function. --- energy increment. --- energy regularity. --- energy variation. --- energy. --- error term. --- error. --- finite time interval. --- first material derivative. --- fluid dynamics. --- frequencies. --- frequency energy levels. --- h-principle. --- integral. --- lifespan parameter. --- lower indices. --- material derivative. --- mollification. --- mollifier. --- moment vanishing condition. --- momentum. --- multi-index. --- non-negative function. --- nonzero solution. --- optimal regularity. --- oscillatory factor. --- oscillatory term. --- parameters. --- parametrix expansion. --- parametrix. --- phase direction. --- phase function. --- phase gradient. --- pressure correction. --- pressure. --- regularity. --- relative acceleration. --- relative velocity. --- scaling symmetry. --- second material derivative. --- smooth function. --- smooth stress tensor. --- smooth vector field. --- spatial derivative. --- stress. --- tensor. --- theorem. --- time cutoff function. --- time derivative. --- transport derivative. --- transport equations. --- transport estimate. --- transport. --- upper indices. --- vector amplitude. --- velocity correction. --- velocity field. --- velocity. --- weak limit. --- weak solution.


Book
Reading clocks, alla Turca
Author:
ISBN: 022625786X 9780226257860 9780226257723 Year: 2015 Publisher: Chicago London

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Up until the end of the eighteenth century, the way Ottomans used their clocks conformed to the inner logic of their own temporal culture. However, this began to change rather dramatically during the nineteenth century, as the Ottoman Empire was increasingly assimilated into the European-dominated global economy and the project of modern state building began to gather momentum. In Reading Clocks, Alla Turca, Avner Wishnitzer unravels the complexity of Ottoman temporal culture and for the first time tells the story of its transformation. He explains that in their attempt to attain better surveillance capabilities and higher levels of regularity and efficiency, various organs of the reforming Ottoman state developed elaborate temporal constructs in which clocks played an increasingly important role. As the reform movement spread beyond the government apparatus, emerging groups of officers, bureaucrats, and urban professionals incorporated novel time-related ideas, values, and behaviors into their self-consciously "modern" outlook and lifestyle. Acculturated in the highly regimented environment of schools and barracks, they came to identify efficiency and temporal regularity with progress and the former temporal patterns with the old political order. Drawing on a wealth of archival and literary sources, Wishnitzer's original and highly important work presents the shifting culture of time as an arena in which Ottoman social groups competed for legitimacy and a medium through which the very concept of modernity was defined. Reading Clocks, Alla Turca breaks new ground in the study of the Middle East and presents us with a new understanding of the relationship between time and modernity.


Book
Microlocal and Time-Frequency Analysis
Authors: ---
Year: 2022 Publisher: Basel MDPI - Multidisciplinary Digital Publishing Institute

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The present volume collects the contributions selected for publication in the Special Issue entitled "Microlocal and Time-Frequency Analysis" of the journal Mathematics, edited by Elena Cordero and S. Ivan Trapasso over 2020 and 2021.

Keywords

Computing & information technology --- Computer science --- pseudodifferential operators --- Gevrey regularity --- sharp Gårding inequality --- p-evolution equations --- ultradifferentiable functions --- ultradistributions --- extended Gevrey regularity --- boundary values of analytic functions --- wave front sets --- Rio Papaloapan Bridge --- vibration signals --- damage identification --- wavelet energy accumulation method --- admissibility condition --- the continuous wavelet transform --- inversion formula --- semi-discrete wavelet transform --- tight frames --- covriance matrix --- polar duality --- uncertainty principle --- reconstruction problem --- BBM equation --- ill-posedness --- Fourier amalgam spaces --- Wiener amalgam spaces --- Fourier–Lebesgue spaces --- modulation spaces --- bounded measures --- convolution --- homogeneous Banach spaces --- integrated group representation --- Segal algebra --- Wiener amalgam space --- bounded uniform partition of unity --- locally compact groups --- pseudodifferential operators --- Gevrey regularity --- sharp Gårding inequality --- p-evolution equations --- ultradifferentiable functions --- ultradistributions --- extended Gevrey regularity --- boundary values of analytic functions --- wave front sets --- Rio Papaloapan Bridge --- vibration signals --- damage identification --- wavelet energy accumulation method --- admissibility condition --- the continuous wavelet transform --- inversion formula --- semi-discrete wavelet transform --- tight frames --- covriance matrix --- polar duality --- uncertainty principle --- reconstruction problem --- BBM equation --- ill-posedness --- Fourier amalgam spaces --- Wiener amalgam spaces --- Fourier–Lebesgue spaces --- modulation spaces --- bounded measures --- convolution --- homogeneous Banach spaces --- integrated group representation --- Segal algebra --- Wiener amalgam space --- bounded uniform partition of unity --- locally compact groups


Dissertation
Traitement des signaux bruités via l'analyse multirésolution
Authors: --- --- --- --- --- et al.
Year: 2019 Publisher: Liège Université de Liège (ULiège)

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Nous nous intéressons au traitement de signaux bruités, mais plus particulièrement sur une méthode appelée le soft thresholding. Nous développons dans un premier temps tous les outils nécessaires à la bonne compréhension du soft thresholding. Le premier chapitre est consacré aux ondelettes et à l'analyse multirésolution. Ensuite, Nous étudions l'algorithme de Mallat, utiles pour obtenir les coefficients d'ondelettes d'un signal. Le dernier outil est l'objet du troisième chapitre, consacré à une brève description des espaces de Hölder et de Besov. Enfin, tous les outils précédemment vus sont utilisés dans ce dernier chapitre afin d'étudier le traitement du signal. La majeure partie est consacrée au soft thresholding. Nous étudions d'abord son erreur moyenne quadratique, pour enfin étudier la régularité des signaux traités. Une section est également consacrée à quelques généralités sur le hard thresholding. We are interested in signal processing, but more specifically in the soft thresholding. First of, we develop some necessary tools to understand properly the soft thresholding. The first chapter is devoted to wavelets and multiresolution analysis. Then, we study the Mallat algorithm which is usefull to obtain the wavelets coefficients of a signal. Last but not least, we introduce Hölder and Besov spaces. All the previous chapters are used to develop the soft thresholding. The major part of the last chapter is devoted to the soft thresholding; we study the mean squared error of it and the regularity of a processed signal. A brief introduction to the hard thresholding ends this paper.


Book
Degenerate Diffusion Operators Arising in Population Biology (AM-185)
Authors: ---
ISBN: 1400847184 1299051456 1400846102 9781400846108 9780691157122 069115712X 9780691157153 0691157154 9781299051454 Year: 2013 Publisher: Princeton, NJ

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This book provides the mathematical foundations for the analysis of a class of degenerate elliptic operators defined on manifolds with corners, which arise in a variety of applications such as population genetics, mathematical finance, and economics. The results discussed in this book prove the uniqueness of the solution to the Martingale problem and therefore the existence of the associated Markov process. Charles Epstein and Rafe Mazzeo use an "integral kernel method" to develop mathematical foundations for the study of such degenerate elliptic operators and the stochastic processes they define. The precise nature of the degeneracies of the principal symbol for these operators leads to solutions of the parabolic and elliptic problems that display novel regularity properties. Dually, the adjoint operator allows for rather dramatic singularities, such as measures supported on high co-dimensional strata of the boundary. Epstein and Mazzeo establish the uniqueness, existence, and sharp regularity properties for solutions to the homogeneous and inhomogeneous heat equations, as well as a complete analysis of the resolvent operator acting on Hölder spaces. They show that the semigroups defined by these operators have holomorphic extensions to the right half-plane. Epstein and Mazzeo also demonstrate precise asymptotic results for the long-time behavior of solutions to both the forward and backward Kolmogorov equations.

Keywords

Elliptic operators. --- Markov processes. --- Population biology --- Analysis, Markov --- Chains, Markov --- Markoff processes --- Markov analysis --- Markov chains --- Markov models --- Models, Markov --- Processes, Markov --- Stochastic processes --- Differential operators, Elliptic --- Operators, Elliptic --- Partial differential operators --- Mathematical models. --- 1-dimensional integral. --- Euclidean model problem. --- Euclidean space. --- Hlder space. --- Hopf boundary point. --- Kimura diffusion equation. --- Kimura diffusion operator. --- Laplace transform. --- Schauder estimate. --- WrightІisher geometry. --- adjoint operator. --- backward Kolmogorov equation. --- boundary behavior. --- degenerate elliptic operator. --- doubling. --- elliptic Kimura operator. --- elliptic equation. --- forward Kolmogorov equation. --- function space. --- general model problem. --- generalized Kimura diffusion. --- heat equation. --- heat kernel. --- higher dimensional corner. --- higher regularity. --- holomorphic semi-group. --- homogeneous Cauchy problem. --- hybrid space. --- hypersurface boundary. --- induction hypothesis. --- induction. --- inhomogeneous problem. --- irregular solution. --- long time asymptotics. --- long-time behavior. --- manifold with corners. --- martingale problem. --- mathematical finance. --- model problem. --- normal form. --- normal vector. --- null-space. --- off-diagonal behavior. --- open orthant. --- parabolic equation. --- perturbation theory. --- polyhedron. --- population genetics. --- probability theory. --- regularity. --- resolvent operator. --- semi-group. --- solution operator. --- uniqueness.


Book
Application and Behavior of Nanomaterials in Water Treatment
Authors: --- ---
ISBN: 3039211722 3039211714 Year: 2019 Publisher: MDPI - Multidisciplinary Digital Publishing Institute

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The book compiles scientific articles describing advances in nanomaterial synthesis and their application in water remediation. The publications treat diverse problems such as dye degradation, heavy metal ion, as well as radioactive element capture and sequestration. There are 10 original research articles and one review article. The latter proposes graphene/CNT and Prussian blue nanocomposites for radioactive 137-cesium extraction from aqueous media. All reports thoroughly characterize the nanomaterials post-synthesis and describe their catalytic, photocatalytic, or ion exchange activities in contaminated water. The dyes studied in the collection are azo dyes, i.e. methylene blue and orange, rhodamine B, phenolic dyes viz. bromophenol blue, and other dyes with sulfonyl groups. Extraction of radioactive elements, including cationic 137Cs+ and anionic 125I?, is also investigated. The omnipresence of ZnO nanoparticles in everyday products and their effects in wastewater are also evaluated. Layered double hydroxide are capable of capturing Ag ions, which then has a catalytic effect on dye degradation. The nanomaterials considered are varied, viz., graphene, CNT, Prussian blue, nanoporous carbon, layered double hydroxides, magnetite, ferrites, organic powders, polymer membranes, bacteria, and inorganic nanomaterials such as MnO and Ag. The book targets an interdisciplinary readership.


Book
Mathematical and Numerical Analysis of Nonlinear Evolution Equations : Advances and Perspectives
Author:
Year: 2020 Publisher: Basel, Switzerland MDPI - Multidisciplinary Digital Publishing Institute

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The topic of this book is the mathematical and numerical analysis of some recent frameworks based on differential equations and their application in the mathematical modeling of complex systems, especially of living matter. First, the recent new mathematical frameworks based on generalized kinetic theory, fractional calculus, inverse theory, Schrödinger equation, and Cahn–Hilliard systems are presented and mathematically analyzed. Specifically, the well-posedness of the related Cauchy problems is investigated, stability analysis is also performed (including the possibility to have Hopf bifurcations), and some optimal control problems are presented. Second, this book is concerned with the derivation of specific models within the previous mentioned frameworks and for complex systems in biology, epidemics, and engineering. This book is addressed to graduate students and applied mathematics researchers involved in the mathematical modeling of complex systems.

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