Parameterized Morse Theory in Low-Dimensional and Symplectic Topology
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The Relation of Cobordism to K-Theories
The Relation of Cobordism to K-Theories PhD student seminar winter term 2006/07 November 7, 2006 In the current winter term 2006/07 we want to learn something about the different flavours of cobordism theory - about its geometric constructions and highly algebraic calculations using spectral sequences. Further we want to learn the modern language of Thom spectra and survey some levels in the tower of the following Thom spectra MO MSO MSpin : : : Mfeg: After that there should be time for various special topics: we could calculate the homology or homotopy of Thom spectra, have a look at the theorem of Hartori-Stong, care about d-,e- and f-invariants, look at K-, KO- and MU-orientations and last but not least prove some theorems of Conner-Floyd type: ∼ MU∗X ⊗MU∗ K∗ = K∗X: Unfortunately, there is not a single book that covers all of this stuff or at least a main part of it. But on the other hand it is not a big problem to use several books at a time. As a motivating introduction I highly recommend the slides of Neil Strickland. The 9 slides contain a lot of pictures, it is fun reading them! • November 2nd, 2006: Talk 1 by Marc Siegmund: This should be an introduction to bordism, tell us the G geometric constructions and mention the ring structure of Ω∗ . You might take the books of Switzer (chapter 12) and Br¨oker/tom Dieck (chapter 2). Talk 2 by Julia Singer: The Pontrjagin-Thom construction should be given in detail. Have a look at the books of Hirsch, Switzer (chapter 12) or Br¨oker/tom Dieck (chapter 3). -
Natural Cadmium Is Made up of a Number of Isotopes with Different Abundances: Cd106 (1.25%), Cd110 (12.49%), Cd111 (12.8%), Cd
CLASSROOM Natural cadmium is made up of a number of isotopes with different abundances: Cd106 (1.25%), Cd110 (12.49%), Cd111 (12.8%), Cd 112 (24.13%), Cd113 (12.22%), Cd114(28.73%), Cd116 (7.49%). Of these Cd113 is the main neutron absorber; it has an absorption cross section of 2065 barns for thermal neutrons (a barn is equal to 10–24 sq.cm), and the cross section is a measure of the extent of reaction. When Cd113 absorbs a neutron, it forms Cd114 with a prompt release of γ radiation. There is not much energy release in this reaction. Cd114 can again absorb a neutron to form Cd115, but the cross section for this reaction is very small. Cd115 is a β-emitter C V Sundaram, National (with a half-life of 53hrs) and gets transformed to Indium-115 Institute of Advanced Studies, Indian Institute of Science which is a stable isotope. In none of these cases is there any large Campus, Bangalore 560 012, release of energy, nor is there any release of fresh neutrons to India. propagate any chain reaction. Vishwambhar Pati The Möbius Strip Indian Statistical Institute Bangalore 560059, India The Möbius strip is easy enough to construct. Just take a strip of paper and glue its ends after giving it a twist, as shown in Figure 1a. As you might have gathered from popular accounts, this surface, which we shall call M, has no inside or outside. If you started painting one “side” red and the other “side” blue, you would come to a point where blue and red bump into each other. -
Algebraic Cobordism
Algebraic Cobordism Marc Levine January 22, 2009 Marc Levine Algebraic Cobordism Outline I Describe \oriented cohomology of smooth algebraic varieties" I Recall the fundamental properties of complex cobordism I Describe the fundamental properties of algebraic cobordism I Sketch the construction of algebraic cobordism I Give an application to Donaldson-Thomas invariants Marc Levine Algebraic Cobordism Algebraic topology and algebraic geometry Marc Levine Algebraic Cobordism Algebraic topology and algebraic geometry Naive algebraic analogs: Algebraic topology Algebraic geometry ∗ ∗ Singular homology H (X ; Z) $ Chow ring CH (X ) ∗ alg Topological K-theory Ktop(X ) $ Grothendieck group K0 (X ) Complex cobordism MU∗(X ) $ Algebraic cobordism Ω∗(X ) Marc Levine Algebraic Cobordism Algebraic topology and algebraic geometry Refined algebraic analogs: Algebraic topology Algebraic geometry The stable homotopy $ The motivic stable homotopy category SH category over k, SH(k) ∗ ∗;∗ Singular homology H (X ; Z) $ Motivic cohomology H (X ; Z) ∗ alg Topological K-theory Ktop(X ) $ Algebraic K-theory K∗ (X ) Complex cobordism MU∗(X ) $ Algebraic cobordism MGL∗;∗(X ) Marc Levine Algebraic Cobordism Cobordism and oriented cohomology Marc Levine Algebraic Cobordism Cobordism and oriented cohomology Complex cobordism is special Complex cobordism MU∗ is distinguished as the universal C-oriented cohomology theory on differentiable manifolds. We approach algebraic cobordism by defining oriented cohomology of smooth algebraic varieties, and constructing algebraic cobordism as the universal oriented cohomology theory. Marc Levine Algebraic Cobordism Cobordism and oriented cohomology Oriented cohomology What should \oriented cohomology of smooth varieties" be? Follow complex cobordism MU∗ as a model: k: a field. Sm=k: smooth quasi-projective varieties over k. An oriented cohomology theory A on Sm=k consists of: D1. -
Recognizing Surfaces
RECOGNIZING SURFACES Ivo Nikolov and Alexandru I. Suciu Mathematics Department College of Arts and Sciences Northeastern University Abstract The subject of this poster is the interplay between the topology and the combinatorics of surfaces. The main problem of Topology is to classify spaces up to continuous deformations, known as homeomorphisms. Under certain conditions, topological invariants that capture qualitative and quantitative properties of spaces lead to the enumeration of homeomorphism types. Surfaces are some of the simplest, yet most interesting topological objects. The poster focuses on the main topological invariants of two-dimensional manifolds—orientability, number of boundary components, genus, and Euler characteristic—and how these invariants solve the classification problem for compact surfaces. The poster introduces a Java applet that was written in Fall, 1998 as a class project for a Topology I course. It implements an algorithm that determines the homeomorphism type of a closed surface from a combinatorial description as a polygon with edges identified in pairs. The input for the applet is a string of integers, encoding the edge identifications. The output of the applet consists of three topological invariants that completely classify the resulting surface. Topology of Surfaces Topology is the abstraction of certain geometrical ideas, such as continuity and closeness. Roughly speaking, topol- ogy is the exploration of manifolds, and of the properties that remain invariant under continuous, invertible transforma- tions, known as homeomorphisms. The basic problem is to classify manifolds according to homeomorphism type. In higher dimensions, this is an impossible task, but, in low di- mensions, it can be done. Surfaces are some of the simplest, yet most interesting topological objects. -
New Ideas in Algebraic Topology (K-Theory and Its Applications)
NEW IDEAS IN ALGEBRAIC TOPOLOGY (K-THEORY AND ITS APPLICATIONS) S.P. NOVIKOV Contents Introduction 1 Chapter I. CLASSICAL CONCEPTS AND RESULTS 2 § 1. The concept of a fibre bundle 2 § 2. A general description of fibre bundles 4 § 3. Operations on fibre bundles 5 Chapter II. CHARACTERISTIC CLASSES AND COBORDISMS 5 § 4. The cohomological invariants of a fibre bundle. The characteristic classes of Stiefel–Whitney, Pontryagin and Chern 5 § 5. The characteristic numbers of Pontryagin, Chern and Stiefel. Cobordisms 7 § 6. The Hirzebruch genera. Theorems of Riemann–Roch type 8 § 7. Bott periodicity 9 § 8. Thom complexes 10 § 9. Notes on the invariance of the classes 10 Chapter III. GENERALIZED COHOMOLOGIES. THE K-FUNCTOR AND THE THEORY OF BORDISMS. MICROBUNDLES. 11 § 10. Generalized cohomologies. Examples. 11 Chapter IV. SOME APPLICATIONS OF THE K- AND J-FUNCTORS AND BORDISM THEORIES 16 § 11. Strict application of K-theory 16 § 12. Simultaneous applications of the K- and J-functors. Cohomology operation in K-theory 17 § 13. Bordism theory 19 APPENDIX 21 The Hirzebruch formula and coverings 21 Some pointers to the literature 22 References 22 Introduction In recent years there has been a widespread development in topology of the so-called generalized homology theories. Of these perhaps the most striking are K-theory and the bordism and cobordism theories. The term homology theory is used here, because these objects, often very different in their geometric meaning, Russian Math. Surveys. Volume 20, Number 3, May–June 1965. Translated by I.R. Porteous. 1 2 S.P. NOVIKOV share many of the properties of ordinary homology and cohomology, the analogy being extremely useful in solving concrete problems. -
Floer Homology, Gauge Theory, and Low-Dimensional Topology
Floer Homology, Gauge Theory, and Low-Dimensional Topology Clay Mathematics Proceedings Volume 5 Floer Homology, Gauge Theory, and Low-Dimensional Topology Proceedings of the Clay Mathematics Institute 2004 Summer School Alfréd Rényi Institute of Mathematics Budapest, Hungary June 5–26, 2004 David A. Ellwood Peter S. Ozsváth András I. Stipsicz Zoltán Szabó Editors American Mathematical Society Clay Mathematics Institute 2000 Mathematics Subject Classification. Primary 57R17, 57R55, 57R57, 57R58, 53D05, 53D40, 57M27, 14J26. The cover illustrates a Kinoshita-Terasaka knot (a knot with trivial Alexander polyno- mial), and two Kauffman states. These states represent the two generators of the Heegaard Floer homology of the knot in its topmost filtration level. The fact that these elements are homologically non-trivial can be used to show that the Seifert genus of this knot is two, a result first proved by David Gabai. Library of Congress Cataloging-in-Publication Data Clay Mathematics Institute. Summer School (2004 : Budapest, Hungary) Floer homology, gauge theory, and low-dimensional topology : proceedings of the Clay Mathe- matics Institute 2004 Summer School, Alfr´ed R´enyi Institute of Mathematics, Budapest, Hungary, June 5–26, 2004 / David A. Ellwood ...[et al.], editors. p. cm. — (Clay mathematics proceedings, ISSN 1534-6455 ; v. 5) ISBN 0-8218-3845-8 (alk. paper) 1. Low-dimensional topology—Congresses. 2. Symplectic geometry—Congresses. 3. Homol- ogy theory—Congresses. 4. Gauge fields (Physics)—Congresses. I. Ellwood, D. (David), 1966– II. Title. III. Series. QA612.14.C55 2004 514.22—dc22 2006042815 Copying and reprinting. Material in this book may be reproduced by any means for educa- tional and scientific purposes without fee or permission with the exception of reproduction by ser- vices that collect fees for delivery of documents and provided that the customary acknowledgment of the source is given. -
On the Bordism Ring of Complex Projective Space Claude Schochet
proceedings of the american mathematical society Volume 37, Number 1, January 1973 ON THE BORDISM RING OF COMPLEX PROJECTIVE SPACE CLAUDE SCHOCHET Abstract. The bordism ring MUt{CPa>) is central to the theory of formal groups as applied by D. Quillen, J. F. Adams, and others recently to complex cobordism. In the present paper, rings Et(CPm) are considered, where E is an oriented ring spectrum, R=7rt(£), andpR=0 for a prime/». It is known that Et(CPcc) is freely generated as an .R-module by elements {ßT\r^0}. The ring structure, however, is not known. It is shown that the elements {/VI^O} form a simple system of generators for £t(CP°°) and that ßlr=s"rß„r mod(/?j, • • • , ßvr-i) for an element s e R (which corre- sponds to [CP"-1] when E=MUZV). This may lead to information concerning Et(K(Z, n)). 1. Introduction. Let E he an associative, commutative ring spectrum with unit, with R=n*E. Then E determines a generalized homology theory £* and a generalized cohomology theory E* (as in G. W. White- head [5]). Following J. F. Adams [1] (and using his notation throughout), assume that E is oriented in the following sense : There is given an element x e £*(CPX) such that £*(S2) is a free R- module on i*(x), where i:S2=CP1-+CP00 is the inclusion. (The Thom-Milnor spectrum MU which yields complex bordism theory and cobordism theory satisfies these hypotheses and is of seminal interest.) By a spectral sequence argument and general nonsense, Adams shows: (1.1) E*(CP ) is the graded ring of formal power series /?[[*]]. -
Manifolds at and Beyond the Limit of Metrisability 1 Introduction
ISSN 1464-8997 125 Geometry & Topology Monographs Volume 2: Proceedings of the Kirbyfest Pages 125–133 Manifolds at and beyond the limit of metrisability David Gauld Abstract In this paper we give a brief introduction to criteria for metris- ability of a manifold and to some aspects of non-metrisable manifolds. Bias towards work currently being done by the author and his colleagues at the University of Auckland will be very evident. Wishing Robion Kirby a happy sixtieth with many more to follow. AMS Classification 57N05, 57N15; 54E35 Keywords Metrisability, non-metrisable manifold 1 Introduction By a manifold we mean a connected, Hausdorff topological space in which each point has a neighbourhood homeomorphic to some euclidean space Rn .Thus we exclude boundaries. Although the manifolds considered here tend, in a sense, to be large, it is straightforward to show that any finite set of points in a manifold lies in an open subset homeomorphic to Rn ; in particular each finite set lies in an arc. Set Theory plays a major role in the study of large manifolds; indeed, it is often the case that the answer to a particular problem depends on the Set Theory involved. On the other hand Algebraic Topology seems to be of less use, at least so far, with [16, Section 5] and [5] being among the few examples. Perhaps it is not surprising that Set Theory is of major use while Algebraic Topology is of minor use given that the former is of greater significance when the size of the sets involved grows, while the latter is most effective when we are dealing with compact sets. -
Bordism and Cobordism
[ 200 ] BORDISM AND COBORDISM BY M. F. ATIYAH Received 28 March 1960 Introduction. In (10), (11) Wall determined the structure of the cobordism ring introduced by Thorn in (9). Among Wall's results is a certain exact sequence relating the oriented and unoriented cobordism groups. There is also another exact sequence, due to Rohlin(5), (6) and Dold(3) which is closely connected with that of Wall. These exact sequences are established by ad hoc methods. The purpose of this paper is to show that both these sequences are ' cohomology-type' exact sequences arising in the well-known way from mappings into a universal space. The appropriate ' cohomology' theory is constructed by taking as universal space the Thom complex MS0(n), for n large. This gives rise to (oriented) cobordism groups MS0*(X) of a space X. We consider also a 'singular homology' theory based on differentiable manifolds, and we define in this way the (oriented) bordism groups MS0*{X) of a space X. The justification for these definitions is that the main theorem of Thom (9) then gives a 'Poincare duality' isomorphism MS0*(X) ~ MSO^(X) for a compact oriented differentiable manifold X. The usual generalizations to manifolds which are open and not necessarily orientable also hold (Theorem (3-6)). The unoriented corbordism group jV'k of Thom enters the picture via the iso- k morphism (4-1) jrk ~ MS0*n- (P2n) (n large), where P2n is real projective 2%-space. The exact sequence of Wall is then just the cobordism sequence for the triad P2n, P2»-i> ^2n-2> while the exact sequence of Rohlin- Dold is essentially the corbordism sequence of the pair P2n, P2n_2. -
On the Motivic Spectra Representing Algebraic Cobordism and Algebraic K-Theory
Documenta Math. 359 On the Motivic Spectra Representing Algebraic Cobordism and Algebraic K-Theory David Gepner and Victor Snaith Received: September 9, 2008 Communicated by Lars Hesselholt Abstract. We show that the motivic spectrum representing alge- braic K-theory is a localization of the suspension spectrum of P∞, and similarly that the motivic spectrum representing periodic alge- braic cobordism is a localization of the suspension spectrum of BGL. In particular, working over C and passing to spaces of C-valued points, we obtain new proofs of the topological versions of these theorems, originally due to the second author. We conclude with a couple of applications: first, we give a short proof of the motivic Conner-Floyd theorem, and second, we show that algebraic K-theory and periodic algebraic cobordism are E∞ motivic spectra. 2000 Mathematics Subject Classification: 55N15; 55N22 1. Introduction 1.1. Background and motivation. Let (X, µ) be an E∞ monoid in the ∞ category of pointed spaces and let β ∈ πn(Σ X) be an element in the stable ∞ homotopy of X. Then Σ X is an E∞ ring spectrum, and we may invert the “multiplication by β” map − − ∞ Σ nβ∧1 Σ nΣ µ µ(β):Σ∞X ≃ Σ∞S0 ∧ Σ∞X −→ Σ−nΣ∞X ∧ Σ∞X −→ Σ−nΣ∞X. to obtain an E∞ ring spectrum −n β∗ Σ β∗ Σ∞X[1/β] := colim{Σ∞X −→ Σ−nΣ∞X −→ Σ−2nΣ∞X −→···} with the property that µ(β):Σ∞X[1/β] → Σ−nΣ∞X[1/β] is an equivalence. ∞ ∞ In fact, as is well-known, Σ X[1/β] is universal among E∞ Σ X-algebras A in which β becomes a unit. -
Arxiv:Math/9703211V1
ON A COMPUTER RECOGNITION OF 3-MANIFOLDS SERGEI V. MATVEEV Abstract. We describe theoretical backgrounds for a computer program that rec- ognizes all closed orientable 3-manifolds up to complexity 8. The program can treat also not necessarily closed 3-manifolds of bigger complexities, but here some unrec- ognizable (by the program) 3-manifolds may occur. Introduction Let M be an orientable 3-manifold such that ∂M is either empty or consists of tori. Then, modulo W. Thurston geometrization conjecture [Scott 1983], M can be decomposed in a unique way into graph-manifolds and hyperbolic pieces. The classification of graph-manifolds is well-known [Waldhausen 1967], and a list of cusped hyperbolic manifolds up to complexity 7 is contained in [Hildebrand, Weeks 1989]. If we possess an information how the pieces are glued together, we can get an explicit description of M as a sum of geometric pieces. Usually such a presentation is sufficient for understanding the intrinsic structure of M; it allows one to label M with a name that distinguishes it from all other manifolds. We describe theoretical backgrounds and a general scheme of a computer algorithm that realizes in part the procedure. Particularly, for all closed orientable manifolds up to complexity 8 (all of them are graph-manifolds, see [Matveev 1990]) the algorithm gives an exact answer. The paper is based on a talk at MSRI workshop on computational and algorithmic methods in three-dimensional topology (March 10-14, 1997). The author wishes to thank MSRI for a friendly atmosphere and good conditions of work. arXiv:math/9703211v1 [math.GT] 26 Mar 1997 1. -
Algebraic Topology - Homework 2
Algebraic Topology - Homework 2 Problem 1. Show that the Klein bottle can be cut into two Mobius strips that intersect along their boundaries. Problem 2. Show that a projective plane contains a Mobius strip. Problem 3. The boundary of a disk D is a circle @D. The boundary of a Mobius strip M is a circle @M. Let ∼ be the equivalence relation defined by the identifying each point on the circle @D bijectively to a point on the circle @M. Let X be the quotient space (D [ M)= ∼. What is this quotient space homeomorphic to? Show this using cut-and-paste techniques. Problem 4. Show that the connected sum of two tori can be expressed as a quotient space of an octagonal disk with sides identified according to the word aba−1b−1cdc−1d−1: Then considering the eight vertices of the octagon, how many points do they represent on the surface. Problem 5. Find a representation of the connected sum of g tori as a quotient space of a polygonal disk with sides identified in pairs. Do the same thing for a connected sum of n projective planes. In each case give the corresponding word that describes this identification. Problem 6. (a) Show that the square disks with edges pasted together according to the words aabb and aba−1b result in homeomorphic surfaces. Hint: Cut along one of the diagonals and glue the two triangular disks together along one of the original edges. (b) Vague question: What does this tell you about some spaces that you know? Problem 7.