DOCSLIB.ORG

SRB MEASURES for ALMOST AXIOM a DIFFEOMORPHISMS José Alves, Renaud Leplaideur

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
SRB MEASURES for ALMOST AXIOM a DIFFEOMORPHISMS José Alves, Renaud Leplaideur SRB MEASURES FOR ALMOST AXIOM A DIFFEOMORPHISMS José Alves, Renaud Leplaideur To cite this version: José Alves, Renaud Leplaideur. SRB MEASURES FOR ALMOST AXIOM A DIFFEOMORPHISMS. 2013. hal-00778407 HAL Id: hal-00778407 https://hal.archives-ouvertes.fr/hal-00778407 Preprint submitted on 20 Jan 2013 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. SRB MEASURES FOR ALMOST AXIOM A DIFFEOMORPHISMS JOSE´ F. ALVES AND RENAUD LEPLAIDEUR Abstract. We consider a diffeomorphism f of a compact manifold M which is Almost Axiom A, i.e. f is hyperbolic in a neighborhood of some compact f-invariant set, except in some singular set of neutral points. We prove that if there exists some f-invariant set of hyperbolic points with positive unstable-Lebesgue measure such that for every point in this set the stable and unstable leaves are \long enough", then f admits a probability SRB measure. Contents 1. Introduction 2 1.1. Background 2 1.2. Statement of results 2 1.3. Overview 4 2. Markov rectangles 5 2.1. Neighborhood of critical zone 5 2.2. First generation of rectangles 6 2.3. Second generation rectangles 7 2.4. Third generation of rectangles 9 3. Proof of Theorem A 10 3.1. Hyperbolic times 10 3.2. Itinerary and cylinders 12 3.3. SRB measure for the induced map 12 3.4. The SRB measure 15 4. Proof of Theorem B 16 4.1. Graph transform 16 4.2. Truncations 19 4.3. Proof of Theorem B 22 References 24 Date: January 20, 2013. 2010 Mathematics Subject Classification. 37D25, 37D30, 37C40. Key words and phrases. Almost Axiom A, SRB measure. JFA was partly supported by FundaCc~aoCalouste Gulbenkian, by CMUP, by the European Regional Development Fund through the Programme COMPETE and by FCT under the projects PTDC/MAT/099493/2008 and PEst-C/MAT/UI0144/2011. RL was partly supported by ANR Dyn- NonHyp and Research in Pair by CIRM. 1 SRB MEASURES FOR ALMOST AXIOM A DIFFEOMORPHISMS 2 1. Introduction 1.1. Background. The goal of this paper is to improve results from [10]. It addresses the question of SRB measures for non-uniformly hyperbolic dynamical systems. We remind that SRB measures are special physical measures, which are measures with observable generic points: For a smooth dynamical system (M; f), meaning that M is a compact smooth Rie- mannian manifold and f is a C1+ diffeomorphism acting on M, we recall that the set Gµ of generic points for a f-invariant ergodic probability measure on M µ, is the set of points x such that for every continuous function φ, n−1 1 X Z lim φ f k(x) = φ dµ. (1.1) n!1 n ◦ k=0 This set has full µ measure. Though holding for a big set of points in terms of µ measure, this convergence can be actually observed only when this set Gµ has strictly positive measure with respect to the volume of the manifold, that is with respect to the Lebesgue measure on M. This volume measure will be denoted by LebM . A measure µ is said to be physical if LebM (Gµ) > 0. The conditions yielding the existence of physical measures for non-uniformly hyper- bolic systems has been studied a lot since the 90's (see e.g. [3, 7, 4, 1]) but still remains not entirely solved. The main reason for that is that physical measure are usually pro- duced under the form of Sinai-Ruelle-Bowen (SRB) measures and there is no general theory to construct the particular Gibbs states that are these SRB measures. One of the explanation of the lack of general theory is probably the large number of ways to degenerate the uniform hyperbolicity. In [10], the author studied a way where the loss of hyperbolicity was due to a critical set S where there was no expansion and no contraction even if the general \hyperbolic" splitting with good angles was still existing on this critical set. Moreover, the non- uniform hyperbolic hypotheses was inspired by the definition of Axiom-A (where there is forward contraction in the stable direction and backward contraction in the unstable direction) but asked for contraction with a lim sup. The main goal of this paper is to prove that this assumption can be released and replaced by a lim inf. Such a result is optimal because this is the weakest possible assumption in the \hyperbolic world". We also emphasize a noticeable second improvement: we prove that the SRB measure constructed is actually a probability measure. As this paper is an improvement of [10], the present paper has a very similar structure to [10] and the statements are also similar. 1.2. Statement of results. We start by defining the class of dynamical systems that we are going to consider. Definition 1.1. Given f : M M a C1+ diffeomorphism and Ω M a compact f- invariant set, we say that f is!Almost Axiom A on Ω if there exists⊂ an open set U Ω such that: ⊃ SRB MEASURES FOR ALMOST AXIOM A DIFFEOMORPHISMS 3 (1) for every x U there is a df-invariant splitting (invariant where it makes sense) 2 u s u s of the tangent space TxM = E (x) E (x) with x E (x) and x E (x) H¨oldercontinuous (with uniformly bounded⊕ H¨olderconstant);7! 7! (2) there exist continuous nonnegative real functions x ku(x) and x ks(x) such that (for some choice of a Riemannian norm 7!on M) for all x 7!U −ks(x) s k k 2 (a) df(x)v f(x) e v x; v E (x), k k ≤ ku(x) k k 8 2 u (b) df(x)v f(x) e v x; v E (x); (3) the exceptionalk k set≥, S = kx k U;8 ku(2x) = ks(x) = 0 , satisfies f(S) = S. f 2 g From here on we assume that f is Almost Axiom A on Ω. The sets S and U Ω u s ⊃ and the functions k and k are fixed as in the definition, and the splitting TxM = Eu(x) Es(x) is called the hyperbolic splitting. ⊕ Definition 1.2. A point x Ω is called a point of integration of the hyperbolic splitting 21 u s if there exist " > 0 and C -disks D" (x) and D"(x) of size " centered at x such that i i i TyD (x) = E (y) for all y D (x) and i = u; s. " 2 " By definition, the set of points of integration is invariant by f. As usual, having the two families of local stable and unstable manifolds defined, we define u [ n u −n s [ −n s n (x) = f D"(−n)(f (x)) and (x) = f D"(n)(f (x)); F n≥0 F n≥0 where "(n) is the size of the disks associated to f n(x). They are called the global stable and unstable manifolds, respectively. Given a point of integration of the hyperbolic splitting x, the manifolds u(x) and s(x) are also immersed Riemannian manifolds. We denote by du and ds theF Riemann- F u s u ian metrics, and by Lebx and Lebx the Riemannian measures, respectively in (x) and s(x). If a measurable partition is subordinated to the unstable foliation Fu (see [11] andF [9]), any f-invariant measure admits a unique system of conditional measuresF with respect to the given partition. Definition 1.3. We say that an invariant and ergodic probability having absolutely u u continuous conditional measures on unstable leaves (x) with respect to Lebx is a Sinai-Ruelle-Bowen (SRB) measure. F Definition 1.4. Given λ > 0, a point x Ω is said to be λ-hyperbolic if 2 1 −n 1 n lim inf log df (x)jEu(x) 6 λ and lim inf log df (x)jEs(x) 6 λ. n!+1 n k k − n!+1 n k k − Definition 1.5. Given λ > 0 and "0 > 0, a point x Ω is called ("0; λ)-regular if the following conditions hold: 2 (1) x is λ-hyperbolic and a point of integration of the hyperbolic splitting; i i (2) (x) contains a disk D (x) of size "0 centered at x, for i = u; s. F "0 An f-invariant compact set Λ Ω is said to be an ("0; λ)-regular set if all points in Λ ⊂ are ("0; λ)-regular. Theorem A. Let Λ be an ("0; λ)-regular set. If there exists some point x0 Λ such u 2 u that LebD (x0)(D" (x0) Λ) > 0, then f has a SRB measure. "0 0 \ SRB MEASURES FOR ALMOST AXIOM A DIFFEOMORPHISMS 4 Note that the hypothesis of Theorem A is very weak. If there exists some probability SRB measure, µ, then, there exists some ("0; λ)-regular set Λ of full µ measure such u u that for µ-a.e. x in Λ, Lebx(D"0 (x) Λ) > 0. On the other hand, a work due to M. Herman ([6]) proves that there exist\ some dynamical systems on the circle such that Lebesgue-almost-every point is \hyperbolic" but there is no SRB measure (even σ-finite).
Load more

Recommended publications
  • Mathematics 144 Set Theory Fall 2012 Version
    MATHEMATICS 144 SET THEORY FALL 2012 VERSION Table of Contents I. General considerations.……………………………………………………………………………………………………….1 1. Overview of the course…………………………………………………………………………………………………1 2. Historical background and motivation………………………………………………………….………………4 3. Selected problems………………………………………………………………………………………………………13 I I. Basic concepts. ………………………………………………………………………………………………………………….15 1. Topics from logic…………………………………………………………………………………………………………16 2. Notation and first steps………………………………………………………………………………………………26 3. Simple examples…………………………………………………………………………………………………………30 I I I. Constructions in set theory.………………………………………………………………………………..……….34 1. Boolean algebra operations.……………………………………………………………………………………….34 2. Ordered pairs and Cartesian products……………………………………………………………………… ….40 3. Larger constructions………………………………………………………………………………………………..….42 4. A convenient assumption………………………………………………………………………………………… ….45 I V. Relations and functions ……………………………………………………………………………………………….49 1.Binary relations………………………………………………………………………………………………………… ….49 2. Partial and linear orderings……………………………..………………………………………………… ………… 56 3. Functions…………………………………………………………………………………………………………… ….…….. 61 4. Composite and inverse function.…………………………………………………………………………… …….. 70 5. Constructions involving functions ………………………………………………………………………… ……… 77 6. Order types……………………………………………………………………………………………………… …………… 80 i V. Number systems and set theory …………………………………………………………………………………. 84 1. The Natural Numbers and Integers…………………………………………………………………………….83 2. Finite induction
    [Show full text]
  • Biography Paper – Georg Cantor
    Mike Garkie Math 4010 – History of Math UCD Denver 4/1/08 Biography Paper – Georg Cantor Few mathematicians are house-hold names; perhaps only Newton and Euclid would qualify. But there is a second tier of mathematicians, those whose names might not be familiar, but whose discoveries are part of everyday math. Examples here are Napier with logarithms, Cauchy with limits and Georg Cantor (1845 – 1918) with sets. In fact, those who superficially familier with Georg Cantor probably have two impressions of the man: First, as a consequence of thinking about sets, Cantor developed a theory of the actual infinite. And second, that Cantor was a troubled genius, crippled by Freudian conflict and mental illness. The first impression is fundamentally true. Cantor almost single-handedly overturned the Aristotle’s concept of the potential infinite by developing the concept of transfinite numbers. And, even though Bolzano and Frege made significant contributions, “Set theory … is the creation of one person, Georg Cantor.” [4] The second impression is mostly false. Cantor certainly did suffer from mental illness later in his life, but the other emotional baggage assigned to him is mostly due his early biographers, particularly the infamous E.T. Bell in Men Of Mathematics [7]. In the racially charged atmosphere of 1930’s Europe, the sensational story mathematician who turned the idea of infinity on its head and went crazy in the process, probably make for good reading. The drama of the controversy over Cantor’s ideas only added spice. 1 Fortunately, modern scholars have corrected the errors and biases in older biographies.
    [Show full text]
  • Bounding, Splitting and Almost Disjointness
    Bounding, splitting and almost disjointness Jonathan Schilhan Advisor: Vera Fischer Kurt G¨odelResearch Center Fakult¨atf¨urMathematik, Universit¨atWien Abstract This bachelor thesis provides an introduction to set theory, cardinal character- istics of the continuum and the generalized cardinal characteristics on arbitrary regular cardinals. It covers the well known ZFC relations of the bounding, the dominating, the almost disjointness and the splitting number as well as some more recent results about their generalizations to regular uncountable cardinals. We also present an overview on the currently known consistency results and formulate open questions. 1 CONTENTS Contents Introduction 3 1 Prerequisites 5 1.1 Model Theory/Predicate Logic . .5 1.2 Ordinals/Cardinals . .6 1.2.1 Ordinals . .7 1.2.2 Cardinals . .9 1.2.3 Regular Cardinals . 10 2 Cardinal Characteristics of the continuum 11 2.1 The bounding and the dominating number . 11 2.2 Splitting and mad families . 13 3 Cardinal Characteristics on regular uncountable cardinals 16 3.1 Generalized bounding, splitting and almost disjointness . 16 3.2 An unexpected inequality between the bounding and splitting numbers . 18 3.2.1 Elementary Submodels . 18 3.2.2 Filters and Ideals . 19 3.2.3 Proof of Theorem 3.2.1 (s(κ) ≤ b(κ)) . 20 3.3 A relation between generalized dominating and mad families . 23 References 28 2 Introduction @0 Since it was proven that the continuum hypothesis (2 = @1) is independent of the axioms of ZFC, the natural question arises what value 2@0 could take and it was shown @0 that 2 could be consistently nearly anything.
    [Show full text]
  • Almost-Free E-Rings of Cardinality ℵ1 Rudige¨ R Gob¨ El, Saharon Shelah and Lutz Strung¨ Mann
    Sh:785 Canad. J. Math. Vol. 55 (4), 2003 pp. 750–765 Almost-Free E-Rings of Cardinality @1 Rudige¨ r Gob¨ el, Saharon Shelah and Lutz Strung¨ mann Abstract. An E-ring is a unital ring R such that every endomorphism of the underlying abelian group R+ is multiplication by some ring element. The existence of almost-free E-rings of cardinality greater @ than 2 0 is undecidable in ZFC. While they exist in Godel'¨ s universe, they do not exist in other models @ of set theory. For a regular cardinal @1 ≤ λ ≤ 2 0 we construct E-rings of cardinality λ in ZFC which have @1-free additive structure. For λ = @1 we therefore obtain the existence of almost-free E-rings of cardinality @1 in ZFC. 1 Introduction + Recall that a unital ring R is an E-ring if the evaluation map ": EndZ(R ) ! R given by ' 7! '(1) is a bijection. Thus every endomorphism of the abelian group R+ is multiplication by some element r 2 R. E-rings were introduced by Schultz [20] and easy examples are subrings of the rationals Q or pure subrings of the ring of p-adic integers. Schultz characterized E-rings of finite rank and the books by Feigelstock [9, 10] and an article [18] survey the results obtained in the eighties, see also [8, 19]. In a natural way the notion of E-rings extends to modules by calling a left R-module M an E(R)-module or just E-module if HomZ(R; M) = HomR(R; M) holds, see [1].
    [Show full text]
  • The Axiom of Choice and Its Implications
    THE AXIOM OF CHOICE AND ITS IMPLICATIONS KEVIN BARNUM Abstract. In this paper we will look at the Axiom of Choice and some of the various implications it has. These implications include a number of equivalent statements, and also some less accepted ideas. The proofs discussed will give us an idea of why the Axiom of Choice is so powerful, but also so controversial. Contents 1. Introduction 1 2. The Axiom of Choice and Its Equivalents 1 2.1. The Axiom of Choice and its Well-known Equivalents 1 2.2. Some Other Less Well-known Equivalents of the Axiom of Choice 3 3. Applications of the Axiom of Choice 5 3.1. Equivalence Between The Axiom of Choice and the Claim that Every Vector Space has a Basis 5 3.2. Some More Applications of the Axiom of Choice 6 4. Controversial Results 10 Acknowledgments 11 References 11 1. Introduction The Axiom of Choice states that for any family of nonempty disjoint sets, there exists a set that consists of exactly one element from each element of the family. It seems strange at first that such an innocuous sounding idea can be so powerful and controversial, but it certainly is both. To understand why, we will start by looking at some statements that are equivalent to the axiom of choice. Many of these equivalences are very useful, and we devote much time to one, namely, that every vector space has a basis. We go on from there to see a few more applications of the Axiom of Choice and its equivalents, and finish by looking at some of the reasons why the Axiom of Choice is so controversial.
    [Show full text]
  • Cardinal Invariants Concerning Functions Whose Sum Is Almost Continuous Krzysztof Ciesielski West Virginia University, [email protected]
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by The Research Repository @ WVU (West Virginia University) Faculty Scholarship 1995 Cardinal Invariants Concerning Functions Whose Sum Is Almost Continuous Krzysztof Ciesielski West Virginia University, [email protected] Follow this and additional works at: https://researchrepository.wvu.edu/faculty_publications Part of the Mathematics Commons Digital Commons Citation Ciesielski, Krzysztof, "Cardinal Invariants Concerning Functions Whose Sum Is Almost Continuous" (1995). Faculty Scholarship. 822. https://researchrepository.wvu.edu/faculty_publications/822 This Article is brought to you for free and open access by The Research Repository @ WVU. It has been accepted for inclusion in Faculty Scholarship by an authorized administrator of The Research Repository @ WVU. For more information, please contact [email protected]. Cardinal invariants concerning functions whose sum is almost continuous. Krzysztof Ciesielski1, Department of Mathematics, West Virginia University, Mor- gantown, WV 26506-6310 ([email protected]) Arnold W. Miller1, York University, Department of Mathematics, North York, Ontario M3J 1P3, Canada, Permanent address: University of Wisconsin-Madison, Department of Mathematics, Van Vleck Hall, 480 Lincoln Drive, Madison, Wis- consin 53706-1388, USA ([email protected]) Abstract Let A stand for the class of all almost continuous functions from R to R and let A(A) be the smallest cardinality of a family F ⊆ RR for which there is no g: R → R with the property that f + g ∈ A for all f ∈ F . We define cardinal number A(D) for the class D of all real functions with the Darboux property similarly.
    [Show full text]
  • Georg Cantor English Version
    GEORG CANTOR (March 3, 1845 – January 6, 1918) by HEINZ KLAUS STRICK, Germany There is hardly another mathematician whose reputation among his contemporary colleagues reflected such a wide disparity of opinion: for some, GEORG FERDINAND LUDWIG PHILIPP CANTOR was a corruptor of youth (KRONECKER), while for others, he was an exceptionally gifted mathematical researcher (DAVID HILBERT 1925: Let no one be allowed to drive us from the paradise that CANTOR created for us.) GEORG CANTOR’s father was a successful merchant and stockbroker in St. Petersburg, where he lived with his family, which included six children, in the large German colony until he was forced by ill health to move to the milder climate of Germany. In Russia, GEORG was instructed by private tutors. He then attended secondary schools in Wiesbaden and Darmstadt. After he had completed his schooling with excellent grades, particularly in mathematics, his father acceded to his son’s request to pursue mathematical studies in Zurich. GEORG CANTOR could equally well have chosen a career as a violinist, in which case he would have continued the tradition of his two grandmothers, both of whom were active as respected professional musicians in St. Petersburg. When in 1863 his father died, CANTOR transferred to Berlin, where he attended lectures by KARL WEIERSTRASS, ERNST EDUARD KUMMER, and LEOPOLD KRONECKER. On completing his doctorate in 1867 with a dissertation on a topic in number theory, CANTOR did not obtain a permanent academic position. He taught for a while at a girls’ school and at an institution for training teachers, all the while working on his habilitation thesis, which led to a teaching position at the university in Halle.
    [Show full text]
  • Almost-At-A-Distance-Accepted
    Almost at-a-distance Andrew McKenzie (Kansas) and Lydia Newkirk (Rutgers) accepted draft in Linguistics & Philosophy [email protected] [email protected] https://doi.org/10.1007/s10988-019-09275-6 Abstract We claim that the meaning of the adverbial almost contains both a scalar proximity measure and a modal that allows it to work sometimes when proximity fails, what we call the at-a-distance reading. Essentially, almost can hold if the proposition follows from the normal uninterrupted out- comes of adding a small enough number of premises to a selection of rel- evant facts. Almost at-a-distance is blocked when the temporal properties of the topic time and Davidsonian event prevent normal outcomes from coming true when they need to. This approach to almost differs from the two general approaches that have emerged in the literature, by replacing the negative polar condition (not p) with a positive antecedent condition that entails not p while avoid- ing the numerous well-documented complications of employing a polar condition. Since this approach to almost involves a circumstantial base with a non-interrupting ordering source, almost behaves in certain ways like the progressive, and shows contextual variability of the same kinds that we see with premise sets. 1 Introduction The adverbial almost has a clear intuitive meaning, but has proven very difficult to reconcile with a formal semantics. Two basic approaches characterize our understanding of almost in the literature. Under scalar alternative accounts, almost p holds when p is false but some close alternative proposition q is true. Modal closeness accounts argue that almost p holds of world w when p is false in w, but true in some close alternative world w0.
    [Show full text]
  • Equivalents to the Axiom of Choice and Their Uses A
    EQUIVALENTS TO THE AXIOM OF CHOICE AND THEIR USES A Thesis Presented to The Faculty of the Department of Mathematics California State University, Los Angeles In Partial Fulfillment of the Requirements for the Degree Master of Science in Mathematics By James Szufu Yang c 2015 James Szufu Yang ALL RIGHTS RESERVED ii The thesis of James Szufu Yang is approved. Mike Krebs, Ph.D. Kristin Webster, Ph.D. Michael Hoffman, Ph.D., Committee Chair Grant Fraser, Ph.D., Department Chair California State University, Los Angeles June 2015 iii ABSTRACT Equivalents to the Axiom of Choice and Their Uses By James Szufu Yang In set theory, the Axiom of Choice (AC) was formulated in 1904 by Ernst Zermelo. It is an addition to the older Zermelo-Fraenkel (ZF) set theory. We call it Zermelo-Fraenkel set theory with the Axiom of Choice and abbreviate it as ZFC. This paper starts with an introduction to the foundations of ZFC set the- ory, which includes the Zermelo-Fraenkel axioms, partially ordered sets (posets), the Cartesian product, the Axiom of Choice, and their related proofs. It then intro- duces several equivalent forms of the Axiom of Choice and proves that they are all equivalent. In the end, equivalents to the Axiom of Choice are used to prove a few fundamental theorems in set theory, linear analysis, and abstract algebra. This paper is concluded by a brief review of the work in it, followed by a few points of interest for further study in mathematics and/or set theory. iv ACKNOWLEDGMENTS Between the two department requirements to complete a master's degree in mathematics − the comprehensive exams and a thesis, I really wanted to experience doing a research and writing a serious academic paper.
    [Show full text]
  • Canonical Models for Fragments of the Axiom of Choice∗
    Canonical models for fragments of the axiom of choice∗ Paul Larson y Jindˇrich Zapletal z Miami University University of Florida June 23, 2015 Abstract We develop a technology for investigation of natural forcing extensions of the model L(R) which satisfy such statements as \there is an ultrafil- ter" or \there is a total selector for the Vitali equivalence relation". The technology reduces many questions about ZF implications between con- sequences of the axiom of choice to natural ZFC forcing problems. 1 Introduction In this paper, we develop a technology for obtaining certain type of consistency results in choiceless set theory, showing that various consequences of the axiom of choice are independent of each other. We will consider the consequences of a certain syntactical form. 2 ! Definition 1.1. AΣ1 sentence Φ is tame if it is of the form 9A ⊂ ! (8~x 2 !! 9~y 2 A φ(~x;~y))^(8~x 2 A (~x)), where φ, are formulas which contain only numerical quantifiers and do not refer to A anymore, and may refer to a fixed analytic subset of 2! as a predicate. The formula are called the resolvent of the sentence. This is a syntactical class familiar from the general treatment of cardinal invari- ants in [11, Section 6.1]. It is clear that many consequences of Axiom of Choice are of this form: Example 1.2. The following statements are tame consequences of the axiom of choice: 1. there is a nonprincipal ultrafilter on !. The resolvent formula is \T rng(x) is infinite”; ∗2000 AMS subject classification 03E17, 03E40.
    [Show full text]
  • Regularity Properties and Determinacy
    Regularity Properties and Determinacy MSc Thesis (Afstudeerscriptie) written by Yurii Khomskii (born September 5, 1980 in Moscow, Russia) under the supervision of Dr. Benedikt L¨owe, and submitted to the Board of Examiners in partial fulfillment of the requirements for the degree of MSc in Logic at the Universiteit van Amsterdam. Date of the public defense: Members of the Thesis Committee: August 14, 2007 Dr. Benedikt L¨owe Prof. Dr. Jouko V¨a¨an¨anen Prof. Dr. Joel David Hamkins Prof. Dr. Peter van Emde Boas Brian Semmes i Contents 0. Introduction............................ 1 1. Preliminaries ........................... 4 1.1 Notation. ........................... 4 1.2 The Real Numbers. ...................... 5 1.3 Trees. ............................. 6 1.4 The Forcing Notions. ..................... 7 2. ClasswiseConsequencesofDeterminacy . 11 2.1 Regularity Properties. .................... 11 2.2 Infinite Games. ........................ 14 2.3 Classwise Implications. .................... 16 3. The Marczewski-Burstin Algebra and the Baire Property . 20 3.1 MB and BP. ......................... 20 3.2 Fusion Sequences. ...................... 23 3.3 Counter-examples. ...................... 26 4. DeterminacyandtheBaireProperty.. 29 4.1 Generalized MB-algebras. .................. 29 4.2 Determinacy and BP(P). ................... 31 4.3 Determinacy and wBP(P). .................. 34 5. Determinacy andAsymmetric Properties. 39 5.1 The Asymmetric Properties. ................. 39 5.2 The General Definition of Asym(P). ............. 43 5.3 Determinacy and Asym(P). ................. 46 ii iii 0. Introduction One of the most intriguing developments of modern set theory is the investi- gation of two-player infinite games of perfect information. Of course, it is clear that applied game theory, as any other branch of mathematics, can be modeled in set theory. But we are talking about the converse: the use of infinite games as a tool to study fundamental set theoretic questions.
    [Show full text]
  • DISCONTINUITY SETS of SOME INTERVAL BIJECTIONS E. De
    International Journal of Pure and Applied Mathematics Volume 79 No. 1 2012, 47-55 AP ISSN: 1311-8080 (printed version) url: http://www.ijpam.eu ijpam.eu DISCONTINUITY SETS OF SOME INTERVAL BIJECTIONS E. de Amo1 §, M. D´ıaz Carrillo2, J. Fern´andez S´anchez3 1,3Departamento de Algebra´ y An´alisis Matem´atico Universidad de Almer´ıa 04120, Almer´ıa, SPAIN 2Departamento de An´alisis Matem´atico Universidad de Granada 18071, Granada, SPAIN Abstract: In this paper we prove that the discontinuity set of any bijective function from [a, b[ to [c, d] is infinite. We then proceed to give a gallery of examples which shows that this is the best we can expect, and that it is possible that any intermediate case exists. We conclude with an example of a (nowhere continuous) bijective function which exhibits a dense graph in the rectangle [a, b[ × [c, d] . AMS Subject Classification: 26A06, 26A09 Key Words: discontinuity set, fixed point 1. Introduction During our investigations [1] concerning on the application of Ergodic Theory of Numbers to generate singular functions (i.e., their derivatives vanish almost everywhere), we came across a bijection from a closed interval to another that it is not closed: c : [0, 1] −→ [0, 1[, given by (segments on some intervals): (n − 1)! n! − 1 1 c (x) := x − + n n2 n + 1 1 1 1 1 which maps 1 − n! , 1 − (n+1)! onto n+1 , n and c(1) = 0. h h h h c 2012 Academic Publications, Ltd. Received: April 19, 2012 url: www.acadpubl.eu §Correspondence author 48 E.
    [Show full text]