A Koksma–Hlawka Inequality for Simplices

Total Page:16

File Type:pdf, Size:1020Kb

A Koksma–Hlawka Inequality for Simplices Springer INdAM Series Volum e 3 Editor-in-Chief V. Ancona Series Editors P. Cannarsa C. Canuto G. Coletti P. Marcellini G. Patrizio T. Ruggeri E. Strickland A. Verra For further volumes: www.springer.com/series/10283 Massimo A. Picardello Editor Trends in Harmonic Analysis Editor Massimo A. Picardello Dipartimento di Matematica Università di Roma “Tor Vergata” Rome, Italy ISSN 2281-518X ISSN 2281-5198 (electronic) Springer INdAM Series ISBN 978-88-470-2852-4 ISBN 978-88-470-2853-1 (eBook) DOI 10.1007/978-88-470-2853-1 Springer Milan Heidelberg New York Dordrecht London Library of Congress Control Number: 2012948292 © Springer-Verlag Italia 2013 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of pub- lication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Dedicated to Alessandro Figà-Talamanca on the occasion of his retirement Preface This book collects some of the scientific contributions of the participants in the Conference in Harmonic Analysis held at the Istituto Nazionale di Alta Matematica from May 30th to June 4th, 2011. It illustrates the wide range of research subjects developed by the Italian research group in harmonic analysis, originally started by Alessandro Figà-Talamanca, to whom the Conference was dedicated on the occasion of his retirement. In 1978, the mathematicians in this newly formed research group started a cycle of conferences to present and share their research progress. These conferences were held in different places almost every year until this Conference, the thirty-first of the series, and the first whose Proceedings are published. This book outlines some of the impressive ramifications of the mathematical de- velopments that began when Figà-Talamanca brought the study of harmonic anal- ysis to Italy; the research group that he nurtured has now expanded to cover many areas, and therefore this book is addressed not only to experts in harmonic analysis, summability of Fourier series and singular integrals, but also to experts in potential theory, symmetric spaces, analysis and partial differential equations on Riemannian manifolds, analysis on graphs, trees, buildings and discrete groups, Lie groups and Lie algebras, and even far-reaching applications such as cellular automata and signal processing and connections with mathematical logic. In the last decades, Alessandro Figà-Talamanca has worked on harmonic analysis on trees, and his influence on ongoing research is also underlined by the fact that several contributions to the present volume, even those dealing with completely different subjects, are related to trees or similar discrete structures. Rome, Italy Massimo Picardello vii Acknowledgements We acknowledge with pleasure the hospitality of the Istituto Nazionale di Alta Matematica and the financial support of the Gruppo Nazionale per l’Analisi Matem- atica, la Probabilità e le Applicazioni. We are very grateful to the referees for their accurate reading of each contributed paper and for their valuable suggestions. The Editor is very grateful to all the authors for the patience that they have shown in kindly and promptly replying to his countless requests for revisions. ix Contents The Shifted Wave Equation on Damek–Ricci Spaces and on Homogeneous Trees ....................... 1 Jean-Philippe Anker, Pierre Martinot, Emmanuel Pedon, and Alberto G. Setti Invariance of Capacity Under Quasisymmetric Maps of the Circle: An Easy Proof ............................... 27 Nicola Arcozzi and Richard Rochberg A Koksma–Hlawka Inequality for Simplices ................ 33 Luca Brandolini, Leonardo Colzani, Giacomo Gigante, and Giancarlo Travaglini A Dual Interpretation of the Gromov–Thurston Proof of Mostow Rigidity and Volume Rigidity for Representations of Hyperbolic Lattices .................................. 47 Michelle Bucher, Marc Burger, and Alessandra Iozzi The Algebras Generated by the Laplace Operators in a Semi- homogeneous Tree ............................ 77 Enrico Casadio Tarabusi and Massimo A. Picardello Surjunctivity and Reversibility of Cellular Automata over Concrete Categories ................................. 91 Tullio Ceccherini-Silberstein and Michel Coornaert Pointwise Convergence of Bochner–Riesz Means in Sobolev Spaces ....135 Leonardo Colzani and Sara Volpi Sub-Finsler Geometry and Finite Propagation Speed ............147 Michael G. Cowling and Alessio Martini On the Boundary Behavior of Holomorphic and Harmonic Functions . 207 Fausto Di Biase xi xii Contents Constructing Laplacians on Limit Spaces of Self-similar Groups .....245 Alfredo Donno Some Remarks on Generalized Gaussian Noise ...............277 Saverio Giulini Eigenvalues of the Vertex Set Hecke Algebra of an Affine Building ....291 Anna Maria Mantero and Anna Zappa A Liouville Type Theorem for Carnot Groups: A Case Study .......371 Alessandro Ottazzi and Ben Warhurst Stochastic Properties of Riemannian Manifolds and Applications to PDE’s ..................................381 Gregorio Pacelli Bessa, Stefano Pigola, and Alberto G. Setti Characterization of Carleson Measures for Besov Spaces on Homogeneous Trees ..........................399 Maria Rosaria Tupputi Atomic and Maximal Hardy Spaces on a Lie Group of Exponential Growth ..................................409 Maria Vallarino The Maximal Singular Integral: Estimates in Terms of the Singular Integral ..................................425 Joan Verdera The Shifted Wave Equation on Damek–Ricci Spaces and on Homogeneous Trees Jean-Philippe Anker, Pierre Martinot, Emmanuel Pedon, and Alberto G. Setti Abstract We solve explicitly the shifted wave equation on Damek–Ricci spaces, using the inverse dual Abel transform and Ásgeirsson’s theorem. As an application, we investigate Huygens’ principle. A similar analysis is carried out in the discrete setting of homogeneous trees. Keywords Abel transform · Damek–Ricci space · Homogeneous tree · Huygens’ principle · Hyperbolic space · Wave equation · Wave propagation Mathematics Subject Classification (2010) Primary 35L05 · 43A85 · Secondary 20F67 · 22E30 · 22E35 · 33C80 · 43A80 · 58J45 J.-P. Anker (B) Fédération Denis Poisson (FR 2964) and Laboratoire MAPMO (UMR 7349), Bâtiment de Mathématiques, Université d’Orléans and CNRS, B.P. 6759, 45067 Orléans Cedex 2, France e-mail: [email protected] P. Martinot 2 rue de la Maladrie, 54630 Flavigny-sur-Moselle, France e-mail: [email protected] E. Pedon Fédération ARC (FR 3399) and Laboratoire de Mathématiques (EA 4535), Université de Reims (Champagne-Ardenne), Moulin de la Housse, B.P. 1039, 51687 Reims Cedex 2, France e-mail: [email protected] A.G. Setti Sezione di Matematica, Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell’Insubria, via Valleggio 11, 22100 Como, Italy e-mail: [email protected] M.A. Picardello (ed.), Trends in Harmonic Analysis, Springer INdAM Series 3, 1 DOI 10.1007/978-88-470-2853-1_1, © Springer-Verlag Italia 2013 2 J.-P. Anker et al. 1 Introduction In the book [17] Helgason uses Ásgeirsson’s mean value theorem (see Theorem II.5.28) to solve the wave equation ∂2u(x, t) = Δ u(x, t), t x (1) u(x, 0) = f(x), ∂t |t=0 u(x, t) = g(x), on Euclidean spaces Rd (see [17, Exercise II.F.1, p. 342] and its solution at pp. 574– 575) and the shifted wave equation ∂2u(x, t) ={Δ + (d − 1)2/4}u(x, t), t x (2) u(x, 0) = f(x), ∂t |t=0 u(x, t) = g(x), on real hyperbolic spaces H d (R) (see [17, Exercise II.F.2, p. 343] and its solution at pp. 575–577). In this work we extend this approach both to Damek–Ricci spaces and to homogeneous trees. Along the way we clarify the role of the inverse dual Abel transform in solving the shifted wave equation. Recall that Damek–Ricci spaces are Riemannian manifolds, which contain all hy- perbolic spaces H d (R), H d (C), H d (H), H 2(O) as a small subclass and share nev- ertheless several features with these spaces.
Recommended publications
  • Surjunctivity and Reversibility of Cellular Automata Over Concrete
    SURJUNCTIVITY AND REVERSIBILITY OF CELLULAR AUTOMATA OVER CONCRETE CATEGORIES TULLIO CECCHERINI-SILBERSTEIN AND MICHEL COORNAERT Abstract. Following ideas developed by Misha Gromov, we investigate surjunctivity and reversibility properties of cellular automata defined over certain concrete categories. Dedicated to Alessandro Fig`aTalamanca 1. Introduction A cellular automaton is an abstract machine which takes as input a configuration of a universe and produces as output another configuration. The universe consists of cells and a configuration is described by the state of each cell of the universe. There is an input and an output state set and these two sets may be distinct. The state sets are also called the sets of colors, the sets of symbols, or the alphabets. The transition rule of a cellular automaton must obey two important properties, namely locality and time-independence. Locality means that the output state of a given cell only depends on the input states of a finite number of its neighboring cells possibly including the cell itself. In the present paper, we restrict ourselves to cellular automata for which the universe is a group. The cells are the elements of the group. If the input alphabet is denoted by A, the output alphabet by B, and the group by G, this means that a cellular automaton is given by a map τ : AG → BG, where AG := {x: G → A} is the set of all input configurations and BG := {y : G → B} is the set of all possible output configurations. Besides locality, we will also always require a symmetry condition for τ, namely that it commutes with the shift actions of G on AG and BG (see Section 2 for precise definitions).
    [Show full text]
  • Springer Monographs in Mathematics for Further Volumes: Tullio Ceccherini-Silberstein R Michel Coornaert
    Springer Monographs in Mathematics For further volumes: www.springer.com/series/3733 Tullio Ceccherini-Silberstein r Michel Coornaert Cellular Automata and Groups Tullio Ceccherini-Silberstein Michel Coornaert Dipartimento di Ingegneria Institut de Recherche Mathématique Avancée Università del Sannio Université de Strasbourg C.so Garibaldi 107 7 rue René-Descartes 82100 Benevento 67084 Strasbourg Cedex Italy France [email protected] [email protected] ISSN 1439-7382 ISBN 978-3-642-14033-4 e-ISBN 978-3-642-14034-1 DOI 10.1007/978-3-642-14034-1 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2010934641 Mathematics Subject Classification (2010): 37B15, 68Q80, 20F65, 43A07, 16S34, 20C07 © Springer-Verlag Berlin Heidelberg 2010 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover design: deblik Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) To Katiuscia, Giacomo, and Tommaso To Martine and Nathalie Preface Two seemingly unrelated mathematical notions, namely that of an amenable group and that of a cellular automaton, were both introduced by John von Neumann in the first half of the last century.
    [Show full text]
  • Expansive Actions with Specification of Sofic Groups, Strong Topological Markov Property, and Surjunctivity
    EXPANSIVE ACTIONS WITH SPECIFICATION OF SOFIC GROUPS, STRONG TOPOLOGICAL MARKOV PROPERTY, AND SURJUNCTIVITY TULLIO CECCHERINI-SILBERSTEIN, MICHEL COORNAERT, AND HANFENG LI Abstract. A dynamical system is a pair (X; G), where X is a compact metrizable space and G is a countable group acting by homeomorphisms of X. An endomorphism of (X; G) is a continuous selfmap of X which commutes with the action of G. One says that a dynamical system (X; G) is surjunctive provided that every injective endomorphism of (X; G) is surjective (and therefore is a homeomorphism). We show that when G is sofic, every expansive dynamical system (X; G) with nonnegative sofic topological entropy and satisfying the weak specification and the strong topological Markov properties, is surjunctive. Contents 1. Introduction 2 2. Preliminaries 5 2.1. General notation 5 2.2. Actions 5 2.3. Shifts and subshifts 5 2.4. Dynamical systems 6 2.5. Expansivity 6 2.6. The strong topological Markov property 7 2.7. The weak specification property 8 2.8. The pseudo-orbit tracing property 8 2.9. Algebraic dynamical systems 9 2.10. The Hamming distance 9 2.11. Sofic groups 9 2.12. Sofic topological entropy 10 3. Proofs 12 4. Examples 17 Appendix A. Stirling's approximation formula 18 References 19 Date: July 26, 2021. 2010 Mathematics Subject Classification. 37B40, 37B10, 37D20, 20F65. Key words and phrases. Sofic group, sofic entropy, surjunctive dynamical system, expansive action, strong topological Markov property, weak specification property, subshift, surjunctive subshift, strongly irreducible subshift, algebraic dynamical system. 1 2 TULLIO CECCHERINI-SILBERSTEIN, MICHEL COORNAERT, AND HANFENG LI 1.
    [Show full text]
  • Open Problems
    Open Problems In the list below we collect some open problems related to the topics treated in this book. (OP-1) Let G be an amenable periodic group which is not locally finite. Does there exist a finite set A and a cellular automaton τ : AG → AG which is surjective but not injective? (OP-2) Let G be a periodic group which is not locally finite and let A be an infinite set. Does there exist a bijective cellular automaton τ : AG → AG which is not invertible? (OP-3) Let G be a periodic group which is not locally finite and let V be an infinite-dimensional vector space over a field K. Does there exist a bijective linear cellular automaton τ : V G → V G which is not invertible? (OP-4) Is every Gromov-hyperbolic group residually finite (resp. residually amenable, resp. sofic, resp. surjunctive)? (OP-5) (Gottschalk’s conjecture) Is every group surjunctive? (OP-6) Let G be a periodic group which is not locally finite and let A be an infinite set. Does there exist a cellular automaton τ : AG → AG whose image τ(AG) is not closed in AG with respect to the prodiscrete topology? (OP-7) Let G be a periodic group which is not locally finite and let V be an infinite-dimensional vector space over a field K. Does there exist a linear cellular automaton τ : V G → V G whose image τ(V G)isnot closed in V G with respect to the prodiscrete topology? (OP-8) Let G and H be two quasi-isometric groups.
    [Show full text]
  • Arxiv:2008.10565V2 [Math.GR] 26 Oct 2020 N Ftems Motn Lse Fgop Ngoercgopthe Group Geometric T in on Groups Life of a Classes Live Important Sofi Now Most Surjunctive
    ON DUAL SURJUNCTIVITY AND APPLICATIONS MICHAL DOUCHA AND JAKUB GISMATULLIN Abstract. We explore the dual version of Gottschalk’s conjecture recently intro- duced by Capobianco, Kari, and Taati, and the notion of dual surjunctivity in general. We show that dual surjunctive groups satisfy Kaplansky’s direct finiteness conjecture for all fields of positive characteristic. By quantifying the notions of injectivity and post-surjectivity for cellular automata, we show that the image of the full topological shift under an injective cellular automaton is a subshift of finite type in a quantitative way. Moreover we show that dual surjunctive groups are closed under ultraproducts, under elementary equivalence, and under certain semidirect products (using the ideas of Arzhantseva and Gal for the latter); they form a closed subset in the space of marked groups, fully residually dual surjunctive groups are dual surjunctive, etc. We also consider dual surjunctive systems for more general dynamical systems, namely for certain expansive algebraic actions, employing results of Chung and Li. Contents Introduction 1 1. Post-surjectivity and pre-injectivity 3 2. More observations on injectivity and post-surjectivity 5 3. Dual surjunctive groups and ultraproducts 8 4. Direct finiteness conjecture 12 5. Metric direct finiteness conjecture 13 6. Expansive dynamical systems 16 References 19 Introduction In the beginning of the 1970s, W. Gottschalk introduced the following notion. Let G be a group and A a finite set, and let us consider the topological Bernoulli shift G y AG. arXiv:2008.10565v2 [math.GR] 26 Oct 2020 If any injective, continuous, and G-equivariant map T : AG → AG is also surjective, then G is called surjunctive.
    [Show full text]