The continuity method
|
|
- Rolf Cooper
- 5 years ago
- Views:
Transcription
1 The continuity method The method of continuity is used in conjunction with a priori estimates to prove the existence of suitably regular solutions to elliptic partial differential equations. One crucial ingredient of the method relies on global a priori estimates of solutions (see the Schauder estimates and the L p regularity theory and this provides one important application of the regularity theory for such equations. 1. The general framework Theorem 1.1. Let B be a Banach space and let T : B B. Assume that there exists θ (0, 1 such that T u T v θ u v. Then there is a unique fixed point u B such that T u = u. Proof. For any u 0 B, define the sequence {u i } by We have that for j > i u j u i j k=i+1 j k=i+1 u i = T u i 1. u k u k 1 = θ k 1 u 1 u 0 θi 1 θ u 1 u 0. j k=i+1 T u k 1 T u k 2 Thus the sequence {u i } is a Cauchy sequence and hence it converges to some u B. By the continuity of T, we have that u = T u. To show the uniqueness, suppose that there exists two solutions u = T u and v = T v. Then, u v = T u T v θ u v < u v and it follows that u = v. Theorem 1.2. Let B be a Banach spaces and V be a normed vector space. Let L 0, L 1 : B V be two bounded linear operators. Set L t := (1 tl 0 + tl 1 for t [0, 1]. 1
2 Assume that there exists a constant C > 0 such that for all u B and t [0, 1], we have u B C L t u V. Then L 0 is surjective if and only if L 1 is surjective. Proof. Suppose that L 0 is surjective. Then L 0 is a bijection, hence the inverse L 1 0 : V B exists. For t [0, 1] and f V, the equation is equivalent to L t u = f L 0 u = f + L 0 u L t u = f + t(l 0 L 1 (u. By the invertibility of L s, it is also equivalent to u = L 1 0 (f + t(l 0 L 1 (u := T u. Hence solving L t u = f is equivalent to find a fixed point to the operator T : B B defined by T u := L 1 0 (f + t(l 0 L 1 (u. We claim that T is a contraction mapping. Indeed T u T v B = L 1 0 (f + t(l 0 L 1 (u L 1 0 (f + t(l 0 L 1 (v B = t L 1 0 (L 0 L1(u v B tc (L 0 L 1 (u v B tc( L 0 + L 1 u v B 1 and hence if tc( L 0 + L 1 < 1 that is if t < 2δ = C( L 0 + L 1, then T is a contraction. Hence for t δ = t 1, T admits a fixed point. Then starting from t 1, we get t 2 and so forth. So we can divide the interval [0, 1] into subintervals of length less than δ until we rich 1. Also L 1 u = f is solvable. This completes the proof of the theorem. 2. Existence of classical solutions Schauder estimates for general equations. Theorem 2.1. Let be a bounded C 2,α domain, f C α ( and g C 2,α ( for some α (0, 1. Then, the Dirichlet problem { u = f in (1 u = g on. posses a unique solution u of class C 2,α (. 2
3 Proof. The uniqueness follows from the maximum principle. The existence follows from approximating f by smooth functions, using the regularity for C rhs and the a priori estimates of Schauder which gives a compactness result. Let be a bounded domain, let a ij, b i and c be defined in with a ij symmetric. Consider the second-order elliptic operator (2 Lu = ij and assume L is uniformly elliptic a ij (xd i D j u + i λ ξ 2 ij a ij ξ i ξ j Λ ξ 2 b i D i u + cu a ij, b i, c C α ( and a ij C α ( + i ij b i C α ( + c C α ( M. Our aim is to prove a general existence result for solutions of Dirichlet boundary value problem with C 2,α boundary values involving the operator L with C α coefficients. First we need a priori estimates (we suppose that a solution exists. Theorem 2.2 (Weak maximum principle. Let u C 2 ( C( be a solution to (2 with c 0. Then u L ( C( f L ( + sup u where C = depends on n, λ, Λ, and the L norm of the coefficients. Proof. First we prove that sup u sup u + + C f L (. First we suppose that c(x c 0 > 0 and consider v := u u +. We have that v satisfies Lv = f csup u + f in and v 0 on the boundary. If v attains a positive maximum at an interior point x 0, then c 0 v(x 0 c(x 0 v(x 0 f(x 0 f L (. It follows that sup v f L (, and hence c 0 sup u sup u + + f L ( c 0. 3
4 In the general case c 0, we write v = z v = zw for an appropriate z z > 0 to be determined. We have that w satisfies a ij D ij w + ( b i 2 a ij D j z D i w z ij i j ( + c + 1 z ( b i D i z a ij D ij z w f z. i i,j Choosing z bounded and such that z > 0 and 1 z ( i b id i z a ij D ij z > i,j c 0, we see that w satisfies and equation with c > 0. Hence we can aplly the previous arguments to show that sup w C f/z L i nfty( and recalling that w = v/z we get the desired result for v and consequently sup u sup u + + C f L (. Applying this for u and u we get the result. Proposition 2.3. Let be a C 2,α domain and let u C 2,α (. Then given ε > 0 there exists a constant C(ε, such that for k = 0, 1 and β (0, 1 and k = 2 and β < α, we have u C k,β ( ε D2 u C 2,α ( + C u L (. We now try to extend our results on the Poisson equation to the case of non-constant coefficients, which was in fact our original goal. Theorem 2.4 (Schauder estimates for general elliptic equations. Let α (0, 1. Let be a bounded C 2,α domain and let L be a uniformly elliptic operator of the form (2 with C α coefficients. Assume also that f C α ( and g C 2,α (. If u C 2,α ( is a solution to (2, then we have the estimate u C 2,α ( ( f C C α ( + g C 2,α ( + u L (, where the constant C depends on n, λ, Λ,, α and the Hölder norms of a ij, b i and c. Proof. Thanks to the interpolation proposition we only need to bound the C 2,α semi-norm with the above rhs. Without loss of generality we can assume that g = 0 (convider v = u g which solves Lv = f Lg = f. We can also reduce the problem by dropping the lower order term. Indeed we can write (2 as ij a ij (xd ij u = f 4
5 where f := f i b id i u cu. If we can show that u C 2,α ( C f then using the interpolation inequality: for all ε > 0 and C α ( u C 2,α ( we have we get that u C 1,α ( ε u C 2,α ( + C(n,,, ε u L ( u C 2,α ( C ( f C α ( + u L ( and using the maximum principle (u = 0 on the boundary u L ( C f L (, we have u C 2,α ( ( f C C α (, Hence the problem is reduced to prove the estimate for the special case, (3 ij a ij (xd ij u = f We use the so called method of freezing coefficients. Th idea is to fix a point x 0 and to rewrite (3 as ij a ij (x 0 D ij u(x = f(x + (a ij (x a ij (x 0 D ij u(x =: h(x. Now a ij (x 0 is positive definite matrix with constant coefficients. After a change of variable, we can reduce the equation to a Poisson equation û = ĥ and use the result of the previous chapter concerning Schauder estimates for the Poisson equation. Note B R a ball centered at x 0 and suppose that u is supported in B R. First we have ĥ C α (B R C( f C α (B R + R α D 2 u C α (B R + u C 2 (B R. Using that a ij (x a ij (x 0 CR α (coefficients are Hölder continuous and the interpolation proposition, we have ĥ C α (B R C( f C α (B R + R α D 2 u C α (B R + u L (B R. ĥ L (B R C( f L (B R + R α D 2 u L (B R + u L (B R. From Theorem 5.13 in the lecture notes, we have ( D 2 u C α (B R C ĥ C α (B R + 1 ĥ + 1 R α L (B R R u 2+α L (B R 5
6 ( 1/α 1 So if we take R 0 =, then for 0 < R R 0, 2C ( D 2 u C α (B R C f C α (B R + u L (B R. The interpolation proposition gives the estimate for the full norm. This Theorem gives still just an interior Schauder type estimate by taking a cut-off function and covering any subdomain by finitely many balls of radius R 0 /2. Next we extend it to the boundary (proof omitted see the books of Wu, Yin, Wang. Existence of classical solutions. Idea: we can solve Dirichlet problems for general elliptic operators with Hölder continuous coefficients, provided that we can solve the equation for the Laplacian. Theorem 2.5. Let be a bounded C 2,α domain and let L be a uniformly elliptic operator of the form (2 with C α coefficients and c 0. Then for any f C α ( and g C 2,α (, there exists a unique solution u C 2,α ( of the Dirichlet problem { Lu = f in (4 u = g in We shall prove the solvability of the boundary value problem (4 if the same is true for the boundary value problem with L 0 = i.e., for Poisson s equation. Of course, the latter is a basic known result and so Theorem follows accordingly. Proof. Since the problems are linear, without loss of generality, we assume g = 0; otherwise, we consider Lv = f Lg with v = 0 on the boundary. Consider the family of equations: L t u := (1 t( u + (1 tlu. We note that L 0 = and L 1 = L. If we write L t u = ij we can easily verify that a t ijd i D j u + i b t id i u + c t u max(1, Λ ξ 2 ij a t ijξ i ξ j min(1, λ ξ 2 for all x and ξ R n and that a t ij C α (, b t i C α (, c t C α ( M 6
7 independently of t. Thus, L t u C α ( C u C 2,α (, where C is a positive constant depending only on n, α, λ, Λ and M. Then for each t [0, 1], L t : B V is a bounded linear operator, where B := { u C 2,α ( u = 0 on } is a Banach space and V := C α ( is a normed vector space. We know that L 0 is solvable (L 0 is surjective, thus if we show the a priori estimates u B = u C 2,α ( C L tu V = C L t u C α ( we are done since the existence of a classical solution (the surjectivity of L 1 is a direct consequence of Theorem 1.2. The uniqueness can be proved by the maximum principle. Since u = 0 on the boundary, the maximum principle implies that u L ( L tu L ( and the global Schauder estimates implies that (since u solves the equation with L t u as a right hand term u C 2,α ( C L tu C α (. 7
TD M1 EDP 2018 no 2 Elliptic equations: regularity, maximum principle
TD M EDP 08 no Elliptic equations: regularity, maximum principle Estimates in the sup-norm I Let be an open bounded subset of R d of class C. Let A = (a ij ) be a symmetric matrix of functions of class
More informationSome lecture notes for Math 6050E: PDEs, Fall 2016
Some lecture notes for Math 65E: PDEs, Fall 216 Tianling Jin December 1, 216 1 Variational methods We discuss an example of the use of variational methods in obtaining existence of solutions. Theorem 1.1.
More informationLecture Notes for LG s Diff. Analysis
Lecture Notes for LG s Diff. Analysis trans. Paul Gallagher Feb. 18, 2015 1 Schauder Estimate Recall the following proposition: Proposition 1.1 (Baby Schauder). If 0 < λ [a ij ] C α B, Lu = 0, then a ij
More informationRegularity for Poisson Equation
Regularity for Poisson Equation OcMountain Daylight Time. 4, 20 Intuitively, the solution u to the Poisson equation u= f () should have better regularity than the right hand side f. In particular one expects
More informationS chauder Theory. x 2. = log( x 1 + x 2 ) + 1 ( x 1 + x 2 ) 2. ( 5) x 1 + x 2 x 1 + x 2. 2 = 2 x 1. x 1 x 2. 1 x 1.
Sep. 1 9 Intuitively, the solution u to the Poisson equation S chauder Theory u = f 1 should have better regularity than the right hand side f. In particular one expects u to be twice more differentiable
More informationCOMPLETE METRIC SPACES AND THE CONTRACTION MAPPING THEOREM
COMPLETE METRIC SPACES AND THE CONTRACTION MAPPING THEOREM A metric space (M, d) is a set M with a metric d(x, y), x, y M that has the properties d(x, y) = d(y, x), x, y M d(x, y) d(x, z) + d(z, y), x,
More informationThe Dirichlet s P rinciple. In this lecture we discuss an alternative formulation of the Dirichlet problem for the Laplace equation:
Oct. 1 The Dirichlet s P rinciple In this lecture we discuss an alternative formulation of the Dirichlet problem for the Laplace equation: 1. Dirichlet s Principle. u = in, u = g on. ( 1 ) If we multiply
More informationBoundary regularity of solutions of degenerate elliptic equations without boundary conditions
Boundary regularity of solutions of elliptic without boundary Iowa State University November 15, 2011 1 2 3 4 If the linear second order elliptic operator L is non with smooth coefficients, then, for any
More informationLecture 17. Higher boundary regularity. April 15 th, We extend our results to include the boundary. Let u C 2 (Ω) C 0 ( Ω) be a solution of
Lecture 7 April 5 th, 004 Higher boundary regularity We extend our results to include the boundary. Higher a priori regularity upto the boundary. Let u C () C 0 ( ) be a solution of Lu = f on, u = ϕ on.
More informationLaplace s Equation. Chapter Mean Value Formulas
Chapter 1 Laplace s Equation Let be an open set in R n. A function u C 2 () is called harmonic in if it satisfies Laplace s equation n (1.1) u := D ii u = 0 in. i=1 A function u C 2 () is called subharmonic
More informationThe De Giorgi-Nash-Moser Estimates
The De Giorgi-Nash-Moser Estimates We are going to discuss the the equation Lu D i (a ij (x)d j u) = 0 in B 4 R n. (1) The a ij, with i, j {1,..., n}, are functions on the ball B 4. Here and in the following
More informationSHARP BOUNDARY TRACE INEQUALITIES. 1. Introduction
SHARP BOUNDARY TRACE INEQUALITIES GILES AUCHMUTY Abstract. This paper describes sharp inequalities for the trace of Sobolev functions on the boundary of a bounded region R N. The inequalities bound (semi-)norms
More informationTheory of PDE Homework 2
Theory of PDE Homework 2 Adrienne Sands April 18, 2017 In the following exercises we assume the coefficients of the various PDE are smooth and satisfy the uniform ellipticity condition. R n is always an
More informationMaximum Principles for Parabolic Equations
Maximum Principles for Parabolic Equations Kamyar Malakpoor 24 November 2004 Textbooks: Friedman, A. Partial Differential Equations of Parabolic Type; Protter, M. H, Weinberger, H. F, Maximum Principles
More informationLECTURE OCTOBER, 2016
18.155 LECTURE 11 18 OCTOBER, 2016 RICHARD MELROSE Abstract. Notes before and after lecture if you have questions, ask! Read: Notes Chapter 2. Unfortunately my proof of the Closed Graph Theorem in lecture
More informationVariational Formulations
Chapter 2 Variational Formulations In this chapter we will derive a variational (or weak) formulation of the elliptic boundary value problem (1.4). We will discuss all fundamental theoretical results that
More informationEquilibria with a nontrivial nodal set and the dynamics of parabolic equations on symmetric domains
Equilibria with a nontrivial nodal set and the dynamics of parabolic equations on symmetric domains J. Földes Department of Mathematics, Univerité Libre de Bruxelles 1050 Brussels, Belgium P. Poláčik School
More informationAnalysis in weighted spaces : preliminary version
Analysis in weighted spaces : preliminary version Frank Pacard To cite this version: Frank Pacard. Analysis in weighted spaces : preliminary version. 3rd cycle. Téhéran (Iran, 2006, pp.75.
More information1. Introduction Boundary estimates for the second derivatives of the solution to the Dirichlet problem for the Monge-Ampere equation
POINTWISE C 2,α ESTIMATES AT THE BOUNDARY FOR THE MONGE-AMPERE EQUATION O. SAVIN Abstract. We prove a localization property of boundary sections for solutions to the Monge-Ampere equation. As a consequence
More informationBoundary problems for fractional Laplacians
Boundary problems for fractional Laplacians Gerd Grubb Copenhagen University Spectral Theory Workshop University of Kent April 14 17, 2014 Introduction The fractional Laplacian ( ) a, 0 < a < 1, has attracted
More informationNotes for Functional Analysis
Notes for Functional Analysis Wang Zuoqin (typed by Xiyu Zhai) October 16, 2015 1 Lecture 11 1.1 The closed graph theorem Definition 1.1. Let f : X Y be any map between topological spaces. We define its
More informationLECTURE # 0 BASIC NOTATIONS AND CONCEPTS IN THE THEORY OF PARTIAL DIFFERENTIAL EQUATIONS (PDES)
LECTURE # 0 BASIC NOTATIONS AND CONCEPTS IN THE THEORY OF PARTIAL DIFFERENTIAL EQUATIONS (PDES) RAYTCHO LAZAROV 1 Notations and Basic Functional Spaces Scalar function in R d, d 1 will be denoted by u,
More informationMinimal Surface equations non-solvability strongly convex functional further regularity Consider minimal surface equation.
Lecture 7 Minimal Surface equations non-solvability strongly convex functional further regularity Consider minimal surface equation div + u = ϕ on ) = 0 in The solution is a critical point or the minimizer
More informationFunctional Analysis. Franck Sueur Metric spaces Definitions Completeness Compactness Separability...
Functional Analysis Franck Sueur 2018-2019 Contents 1 Metric spaces 1 1.1 Definitions........................................ 1 1.2 Completeness...................................... 3 1.3 Compactness......................................
More informationLecture Notes on PDEs
Lecture Notes on PDEs Alberto Bressan February 26, 2012 1 Elliptic equations Let IR n be a bounded open set Given measurable functions a ij, b i, c : IR, consider the linear, second order differential
More informationA metric space X is a non-empty set endowed with a metric ρ (x, y):
Chapter 1 Preliminaries References: Troianiello, G.M., 1987, Elliptic differential equations and obstacle problems, Plenum Press, New York. Friedman, A., 1982, Variational principles and free-boundary
More informationOblique derivative problems for elliptic and parabolic equations, Lecture II
of the for elliptic and parabolic equations, Lecture II Iowa State University July 22, 2011 of the 1 2 of the of the As a preliminary step in our further we now look at a special situation for elliptic.
More informationON WEAKLY NONLINEAR BACKWARD PARABOLIC PROBLEM
ON WEAKLY NONLINEAR BACKWARD PARABOLIC PROBLEM OLEG ZUBELEVICH DEPARTMENT OF MATHEMATICS THE BUDGET AND TREASURY ACADEMY OF THE MINISTRY OF FINANCE OF THE RUSSIAN FEDERATION 7, ZLATOUSTINSKY MALIY PER.,
More informationCourse Description for Real Analysis, Math 156
Course Description for Real Analysis, Math 156 In this class, we will study elliptic PDE, Fourier analysis, and dispersive PDE. Here is a quick summary of the topics will study study. They re described
More informationTools from Lebesgue integration
Tools from Lebesgue integration E.P. van den Ban Fall 2005 Introduction In these notes we describe some of the basic tools from the theory of Lebesgue integration. Definitions and results will be given
More informationThe Dirichlet problem for non-divergence parabolic equations with discontinuous in time coefficients in a wedge
The Dirichlet problem for non-divergence parabolic equations with discontinuous in time coefficients in a wedge Vladimir Kozlov (Linköping University, Sweden) 2010 joint work with A.Nazarov Lu t u a ij
More informationLOWER AND UPPER SOLUTIONS TO SEMILINEAR BOUNDARY VALUE PROBLEMS: AN ABSTRACT APPROACH. Alessandro Fonda Rodica Toader. 1.
Topological Methods in Nonlinear Analysis Journal of the Juliusz Schauder University Centre Volume 38, 2011, 59 93 LOWER AND UPPER SOLUTIONS TO SEMILINEAR BOUNDARY VALUE PROBLEMS: AN ABSTRACT APPROACH
More informationElliptic Partial Differential Equations of Second Order
David Gilbarg Neil S.Trudinger Elliptic Partial Differential Equations of Second Order Reprint of the 1998 Edition Springer Chapter 1. Introduction 1 Part I. Linear Equations Chapter 2. Laplace's Equation
More informationPerron method for the Dirichlet problem.
Introduzione alle equazioni alle derivate parziali, Laurea Magistrale in Matematica Perron method for the Dirichlet problem. We approach the question of existence of solution u C (Ω) C(Ω) of the Dirichlet
More informationERRATUM TO AFFINE MANIFOLDS, SYZ GEOMETRY AND THE Y VERTEX
ERRATUM TO AFFINE MANIFOLDS, SYZ GEOMETRY AND THE Y VERTEX JOHN LOFTIN, SHING-TUNG YAU, AND ERIC ZASLOW 1. Main result The purpose of this erratum is to correct an error in the proof of the main result
More informationP(E t, Ω)dt, (2) 4t has an advantage with respect. to the compactly supported mollifiers, i.e., the function W (t)f satisfies a semigroup law:
Introduction Functions of bounded variation, usually denoted by BV, have had and have an important role in several problems of calculus of variations. The main features that make BV functions suitable
More information= 2 x y 2. (1)
COMPLEX ANALYSIS PART 5: HARMONIC FUNCTIONS A Let me start by asking you a question. Suppose that f is an analytic function so that the CR-equation f/ z = 0 is satisfied. Let us write u and v for the real
More informationPropagation of Smallness and the Uniqueness of Solutions to Some Elliptic Equations in the Plane
Journal of Mathematical Analysis and Applications 267, 460 470 (2002) doi:10.1006/jmaa.2001.7769, available online at http://www.idealibrary.com on Propagation of Smallness and the Uniqueness of Solutions
More informationStationary mean-field games Diogo A. Gomes
Stationary mean-field games Diogo A. Gomes We consider is the periodic stationary MFG, { ɛ u + Du 2 2 + V (x) = g(m) + H ɛ m div(mdu) = 0, (1) where the unknowns are u : T d R, m : T d R, with m 0 and
More informationarxiv: v1 [math.ap] 25 Jul 2012
THE DIRICHLET PROBLEM FOR THE FRACTIONAL LAPLACIAN: REGULARITY UP TO THE BOUNDARY XAVIER ROS-OTON AND JOAQUIM SERRA arxiv:1207.5985v1 [math.ap] 25 Jul 2012 Abstract. We study the regularity up to the boundary
More informationLECTURE 15: COMPLETENESS AND CONVEXITY
LECTURE 15: COMPLETENESS AND CONVEXITY 1. The Hopf-Rinow Theorem Recall that a Riemannian manifold (M, g) is called geodesically complete if the maximal defining interval of any geodesic is R. On the other
More informationFinite Elements. Colin Cotter. January 15, Colin Cotter FEM
Finite Elements January 15, 2018 Why Can solve PDEs on complicated domains. Have flexibility to increase order of accuracy and match the numerics to the physics. has an elegant mathematical formulation
More informationMINIMAL GRAPHS PART I: EXISTENCE OF LIPSCHITZ WEAK SOLUTIONS TO THE DIRICHLET PROBLEM WITH C 2 BOUNDARY DATA
MINIMAL GRAPHS PART I: EXISTENCE OF LIPSCHITZ WEAK SOLUTIONS TO THE DIRICHLET PROBLEM WITH C 2 BOUNDARY DATA SPENCER HUGHES In these notes we prove that for any given smooth function on the boundary of
More informationThe Arzelà-Ascoli Theorem
John Nachbar Washington University March 27, 2016 The Arzelà-Ascoli Theorem The Arzelà-Ascoli Theorem gives sufficient conditions for compactness in certain function spaces. Among other things, it helps
More informationat time t, in dimension d. The index i varies in a countable set I. We call configuration the family, denoted generically by Φ: U (x i (t) x j (t))
Notations In this chapter we investigate infinite systems of interacting particles subject to Newtonian dynamics Each particle is characterized by its position an velocity x i t, v i t R d R d at time
More informationSobolev Spaces. Chapter 10
Chapter 1 Sobolev Spaces We now define spaces H 1,p (R n ), known as Sobolev spaces. For u to belong to H 1,p (R n ), we require that u L p (R n ) and that u have weak derivatives of first order in L p
More informationSYMMETRY OF POSITIVE SOLUTIONS OF SOME NONLINEAR EQUATIONS. M. Grossi S. Kesavan F. Pacella M. Ramaswamy. 1. Introduction
Topological Methods in Nonlinear Analysis Journal of the Juliusz Schauder Center Volume 12, 1998, 47 59 SYMMETRY OF POSITIVE SOLUTIONS OF SOME NONLINEAR EQUATIONS M. Grossi S. Kesavan F. Pacella M. Ramaswamy
More informationFUNCTIONAL ANALYSIS LECTURE NOTES: COMPACT SETS AND FINITE-DIMENSIONAL SPACES. 1. Compact Sets
FUNCTIONAL ANALYSIS LECTURE NOTES: COMPACT SETS AND FINITE-DIMENSIONAL SPACES CHRISTOPHER HEIL 1. Compact Sets Definition 1.1 (Compact and Totally Bounded Sets). Let X be a metric space, and let E X be
More information(convex combination!). Use convexity of f and multiply by the common denominator to get. Interchanging the role of x and y, we obtain that f is ( 2M ε
1. Continuity of convex functions in normed spaces In this chapter, we consider continuity properties of real-valued convex functions defined on open convex sets in normed spaces. Recall that every infinitedimensional
More informationTHE L 2 -HODGE THEORY AND REPRESENTATION ON R n
THE L 2 -HODGE THEORY AND REPRESENTATION ON R n BAISHENG YAN Abstract. We present an elementary L 2 -Hodge theory on whole R n based on the minimization principle of the calculus of variations and some
More informationMATH 263: PROBLEM SET 1: BUNDLES, SHEAVES AND HODGE THEORY
MATH 263: PROBLEM SET 1: BUNDLES, SHEAVES AND HODGE THEORY 0.1. Vector Bundles and Connection 1-forms. Let E X be a complex vector bundle of rank r over a smooth manifold. Recall the following abstract
More informationEconomics 204 Fall 2011 Problem Set 2 Suggested Solutions
Economics 24 Fall 211 Problem Set 2 Suggested Solutions 1. Determine whether the following sets are open, closed, both or neither under the topology induced by the usual metric. (Hint: think about limit
More informationGreen s Functions and Distributions
CHAPTER 9 Green s Functions and Distributions 9.1. Boundary Value Problems We would like to study, and solve if possible, boundary value problems such as the following: (1.1) u = f in U u = g on U, where
More informationModule 7: The Laplace Equation
Module 7: The Laplace Equation In this module, we shall study one of the most important partial differential equations in physics known as the Laplace equation 2 u = 0 in Ω R n, (1) where 2 u := n i=1
More informationLinear Analysis Lecture 5
Linear Analysis Lecture 5 Inner Products and V Let dim V < with inner product,. Choose a basis B and let v, w V have coordinates in F n given by x 1. x n and y 1. y n, respectively. Let A F n n be the
More informationA BOUNDARY VALUE PROBLEM FOR MINIMAL LAGRANGIAN GRAPHS. Simon Brendle & Micah Warren. Abstract. The associated symplectic structure is given by
j. differential geometry 84 (2010) 267-287 A BOUNDARY VALUE PROBLEM FOR MINIMAL LAGRANGIAN GRAPHS Simon Brendle & Micah Warren Abstract Let Ω and Ω be uniformly convex domains in R n with smooth boundary.
More informationLECTURE 1: SOURCES OF ERRORS MATHEMATICAL TOOLS A PRIORI ERROR ESTIMATES. Sergey Korotov,
LECTURE 1: SOURCES OF ERRORS MATHEMATICAL TOOLS A PRIORI ERROR ESTIMATES Sergey Korotov, Institute of Mathematics Helsinki University of Technology, Finland Academy of Finland 1 Main Problem in Mathematical
More informationLandesman-Lazer type results for second order Hamilton-Jacobi-Bellman equations
Author manuscript, published in "Journal of Functional Analysis 258, 12 (2010) 4154-4182" Landesman-Lazer type results for second order Hamilton-Jacobi-Bellman equations Patricio FELMER, Alexander QUAAS,
More informationMAS3706 Topology. Revision Lectures, May I do not answer enquiries as to what material will be in the exam.
MAS3706 Topology Revision Lectures, May 208 Z.A.Lykova It is essential that you read and try to understand the lecture notes from the beginning to the end. Many questions from the exam paper will be similar
More informationNOTES ON SCHAUDER ESTIMATES. r 2 x y 2
NOTES ON SCHAUDER ESTIMATES CRISTIAN E GUTIÉRREZ JULY 26, 2005 Lemma 1 If u f in B r y), then ux) u + r2 x y 2 B r y) B r y) f, x B r y) Proof Let gx) = ux) Br y) u r2 x y 2 Br y) f We have g = u + Br
More informationFIXED POINT ITERATIONS
FIXED POINT ITERATIONS MARKUS GRASMAIR 1. Fixed Point Iteration for Non-linear Equations Our goal is the solution of an equation (1) F (x) = 0, where F : R n R n is a continuous vector valued mapping in
More informationAPPLICATIONS OF DIFFERENTIABILITY IN R n.
APPLICATIONS OF DIFFERENTIABILITY IN R n. MATANIA BEN-ARTZI April 2015 Functions here are defined on a subset T R n and take values in R m, where m can be smaller, equal or greater than n. The (open) ball
More informationis a weak solution with the a ij,b i,c2 C 1 ( )
Thus @u @x i PDE 69 is a weak solution with the RHS @f @x i L. Thus u W 3, loc (). Iterating further, and using a generalized Sobolev imbedding gives that u is smooth. Theorem 3.33 (Local smoothness).
More informationRemarks on the analysis of finite element methods on a Shishkin mesh: are Scott-Zhang interpolants applicable?
Remarks on the analysis of finite element methods on a Shishkin mesh: are Scott-Zhang interpolants applicable? Thomas Apel, Hans-G. Roos 22.7.2008 Abstract In the first part of the paper we discuss minimal
More informationNONTRIVIAL SOLUTIONS TO INTEGRAL AND DIFFERENTIAL EQUATIONS
Fixed Point Theory, Volume 9, No. 1, 28, 3-16 http://www.math.ubbcluj.ro/ nodeacj/sfptcj.html NONTRIVIAL SOLUTIONS TO INTEGRAL AND DIFFERENTIAL EQUATIONS GIOVANNI ANELLO Department of Mathematics University
More informationChapter 7: Bounded Operators in Hilbert Spaces
Chapter 7: Bounded Operators in Hilbert Spaces I-Liang Chern Department of Applied Mathematics National Chiao Tung University and Department of Mathematics National Taiwan University Fall, 2013 1 / 84
More informationPartial regularity for fully nonlinear PDE
Partial regularity for fully nonlinear PDE Luis Silvestre University of Chicago Joint work with Scott Armstrong and Charles Smart Outline Introduction Intro Review of fully nonlinear elliptic PDE Our result
More informationA generalised Ladyzhenskaya inequality and a coupled parabolic-elliptic problem
A generalised Ladyzhenskaya inequality and a coupled parabolic-elliptic problem Dave McCormick joint work with James Robinson and José Rodrigo Mathematics and Statistics Centre for Doctoral Training University
More informationDeforming conformal metrics with negative Bakry-Émery Ricci Tensor on manifolds with boundary
Deforming conformal metrics with negative Bakry-Émery Ricci Tensor on manifolds with boundary Weimin Sheng (Joint with Li-Xia Yuan) Zhejiang University IMS, NUS, 8-12 Dec 2014 1 / 50 Outline 1 Prescribing
More informationξ,i = x nx i x 3 + δ ni + x n x = 0. x Dξ = x i ξ,i = x nx i x i x 3 Du = λ x λ 2 xh + x λ h Dξ,
1 PDE, HW 3 solutions Problem 1. No. If a sequence of harmonic polynomials on [ 1,1] n converges uniformly to a limit f then f is harmonic. Problem 2. By definition U r U for every r >. Suppose w is a
More informationTHE INVERSE FUNCTION THEOREM FOR LIPSCHITZ MAPS
THE INVERSE FUNCTION THEOREM FOR LIPSCHITZ MAPS RALPH HOWARD DEPARTMENT OF MATHEMATICS UNIVERSITY OF SOUTH CAROLINA COLUMBIA, S.C. 29208, USA HOWARD@MATH.SC.EDU Abstract. This is an edited version of a
More informationKrein-Rutman Theorem and the Principal Eigenvalue
Chapter 1 Krein-Rutman Theorem and the Principal Eigenvalue The Krein-Rutman theorem plays a very important role in nonlinear partial differential equations, as it provides the abstract basis for the proof
More informationFinite difference method for elliptic problems: I
Finite difference method for elliptic problems: I Praveen. C praveen@math.tifrbng.res.in Tata Institute of Fundamental Research Center for Applicable Mathematics Bangalore 560065 http://math.tifrbng.res.in/~praveen
More informationLecture 11 Hyperbolicity.
Lecture 11 Hyperbolicity. 1 C 0 linearization near a hyperbolic point 2 invariant manifolds Hyperbolic linear maps. Let E be a Banach space. A linear map A : E E is called hyperbolic if we can find closed
More informationElementary Theory and Methods for Elliptic Partial Differential Equations. John Villavert
Elementary Theory and Methods for Elliptic Partial Differential Equations John Villavert Contents 1 Introduction and Basic Theory 4 1.1 Harmonic Functions............................... 5 1.1.1 Mean Value
More informationELLIPTIC PARTIAL DIFFERENTIAL EQUATIONS EXERCISES I (HARMONIC FUNCTIONS)
ELLIPTIC PARTIAL DIFFERENTIAL EQUATIONS EXERCISES I (HARMONIC FUNCTIONS) MATANIA BEN-ARTZI. BOOKS [CH] R. Courant and D. Hilbert, Methods of Mathematical Physics, Vol. Interscience Publ. 962. II, [E] L.
More informationImplicit Functions, Curves and Surfaces
Chapter 11 Implicit Functions, Curves and Surfaces 11.1 Implicit Function Theorem Motivation. In many problems, objects or quantities of interest can only be described indirectly or implicitly. It is then
More informationEconomics 204 Summer/Fall 2011 Lecture 5 Friday July 29, 2011
Economics 204 Summer/Fall 2011 Lecture 5 Friday July 29, 2011 Section 2.6 (cont.) Properties of Real Functions Here we first study properties of functions from R to R, making use of the additional structure
More informationHamburger Beiträge zur Angewandten Mathematik
Hamburger Beiträge zur Angewandten Mathematik Numerical analysis of a control and state constrained elliptic control problem with piecewise constant control approximations Klaus Deckelnick and Michael
More informationNONLINEAR SCHRÖDINGER ELLIPTIC SYSTEMS INVOLVING EXPONENTIAL CRITICAL GROWTH IN R Introduction
Electronic Journal of Differential Equations, Vol. 014 (014), No. 59, pp. 1 1. ISSN: 107-6691. URL: http://ejde.math.txstate.edu or http://ejde.math.unt.edu ftp ejde.math.txstate.edu NONLINEAR SCHRÖDINGER
More informationNavier Stokes and Euler equations: Cauchy problem and controllability
Navier Stokes and Euler equations: Cauchy problem and controllability ARMEN SHIRIKYAN CNRS UMR 888, Department of Mathematics University of Cergy Pontoise, Site Saint-Martin 2 avenue Adolphe Chauvin 9532
More informationTHE INVERSE FUNCTION THEOREM
THE INVERSE FUNCTION THEOREM W. PATRICK HOOPER The implicit function theorem is the following result: Theorem 1. Let f be a C 1 function from a neighborhood of a point a R n into R n. Suppose A = Df(a)
More information1 Definition of the Riemann integral
MAT337H1, Introduction to Real Analysis: notes on Riemann integration 1 Definition of the Riemann integral Definition 1.1. Let [a, b] R be a closed interval. A partition P of [a, b] is a finite set of
More informationMaximum Principles for Elliptic and Parabolic Operators
Maximum Principles for Elliptic and Parabolic Operators Ilia Polotskii 1 Introduction Maximum principles have been some of the most useful properties used to solve a wide range of problems in the study
More informationChapter 2 Metric Spaces
Chapter 2 Metric Spaces The purpose of this chapter is to present a summary of some basic properties of metric and topological spaces that play an important role in the main body of the book. 2.1 Metrics
More informationThe oblique derivative problem for general elliptic systems in Lipschitz domains
M. MITREA The oblique derivative problem for general elliptic systems in Lipschitz domains Let M be a smooth, oriented, connected, compact, boundaryless manifold of real dimension m, and let T M and T
More informationLecture Notes: African Institute of Mathematics Senegal, January Topic Title: A short introduction to numerical methods for elliptic PDEs
Lecture Notes: African Institute of Mathematics Senegal, January 26 opic itle: A short introduction to numerical methods for elliptic PDEs Authors and Lecturers: Gerard Awanou (University of Illinois-Chicago)
More informationUniversité de Metz. Master 2 Recherche de Mathématiques 2ème semestre. par Ralph Chill Laboratoire de Mathématiques et Applications de Metz
Université de Metz Master 2 Recherche de Mathématiques 2ème semestre Systèmes gradients par Ralph Chill Laboratoire de Mathématiques et Applications de Metz Année 26/7 1 Contents Chapter 1. Introduction
More informationSecond Order Elliptic PDE
Second Order Elliptic PDE T. Muthukumar tmk@iitk.ac.in December 16, 2014 Contents 1 A Quick Introduction to PDE 1 2 Classification of Second Order PDE 3 3 Linear Second Order Elliptic Operators 4 4 Periodic
More informationEuler Equations: local existence
Euler Equations: local existence Mat 529, Lesson 2. 1 Active scalars formulation We start with a lemma. Lemma 1. Assume that w is a magnetization variable, i.e. t w + u w + ( u) w = 0. If u = Pw then u
More informationFunctional Analysis Exercise Class
Functional Analysis Exercise Class Week 9 November 13 November Deadline to hand in the homeworks: your exercise class on week 16 November 20 November Exercises (1) Show that if T B(X, Y ) and S B(Y, Z)
More informationNew Helmholtz-Weyl decomposition in L r and its applications to the mathematical fluid mechanics
New Helmholtz-Weyl decomposition in L r and its applications to the mathematical fluid mechanics Hideo Kozono Mathematical Institute Tohoku University Sendai 980-8578 Japan Taku Yanagisawa Department of
More informationREGULARITY RESULTS FOR THE EQUATION u 11 u 22 = Introduction
REGULARITY RESULTS FOR THE EQUATION u 11 u 22 = 1 CONNOR MOONEY AND OVIDIU SAVIN Abstract. We study the equation u 11 u 22 = 1 in R 2. Our results include an interior C 2 estimate, classical solvability
More informationDIRECT ERROR BOUNDS FOR SYMMETRIC RBF COLLOCATION
Meshless Methods in Science and Engineering - An International Conference Porto, 22 DIRECT ERROR BOUNDS FOR SYMMETRIC RBF COLLOCATION Robert Schaback Institut für Numerische und Angewandte Mathematik (NAM)
More informationPARTIAL DIFFERENTIAL EQUATIONS. Lecturer: D.M.A. Stuart MT 2007
PARTIAL DIFFERENTIAL EQUATIONS Lecturer: D.M.A. Stuart MT 2007 In addition to the sets of lecture notes written by previous lecturers ([1, 2]) the books [4, 7] are very good for the PDE topics in the course.
More informationIt follows from the above inequalities that for c C 1
3 Spaces L p 1. In this part we fix a measure space (, A, µ) (we may assume that µ is complete), and consider the A -measurable functions on it. 2. For f L 1 (, µ) set f 1 = f L 1 = f L 1 (,µ) = f dµ.
More informationContinuity of convex functions in normed spaces
Continuity of convex functions in normed spaces In this chapter, we consider continuity properties of real-valued convex functions defined on open convex sets in normed spaces. Recall that every infinitedimensional
More informationIt follows from the above inequalities that for c C 1
3 Spaces L p 1. Appearance of normed spaces. In this part we fix a measure space (, A, µ) (we may assume that µ is complete), and consider the A - measurable functions on it. 2. For f L 1 (, µ) set f 1
More informationSolution Sheet 3. Solution Consider. with the metric. We also define a subset. and thus for any x, y X 0
Solution Sheet Throughout this sheet denotes a domain of R n with sufficiently smooth boundary. 1. Let 1 p
More informationPartial Differential Equations
Part II Partial Differential Equations Year 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2015 Paper 4, Section II 29E Partial Differential Equations 72 (a) Show that the Cauchy problem for u(x,
More information