Geometric topology of generalized 3-manifolds

In this paper, we describe the history and the present status of one of the main classical problems in low-dimensional geometric topology—the recognition of topological 3-manifolds in the class of all generalized 3-manifolds (i.e., ANR homology 3-manifolds). This problem naturally splits into the cell-like resolution problem for 3-manifolds by means of homology 3-manifolds and the general-position problem for topological 3-manifolds. We have also included some open problems. __________ Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 11, No. 4, pp. 71–84, 2005.     

Link Homology in 4-Manifolds

We define link homology in 4-manifolds, and show that it hasa close connection to linking numbers and intersection matricesof 4-manifolds. We also define null-homologous links in 4-manifolds.We give a necessary and sufficient condition for links to benull-homologous in 4-manifolds. This condition implies thatfor any 4-manifold with second Betti number n, there are (n+ 2)-component links which are not nullhomologous in the 4-manifold.     

Vanishing structure set of Haken 3-manifolds

In this article we prove that the surgery groups of the fundamental group of a certain class of Haken 3-manifolds can be computed in terms of a generalized homology theory even if the manifolds do not support any nonpositively curved Riemannian metric. A consequence of this result is that the integral Novikov conjecture is true for the fundamental group of this class of manifolds. Received October 2, 1998 / in revised form February 10, 2000 / Published online July 20, 2000     

Circle actions on simply connected 5-manifolds

The aim of this paper is to study compact 5-manifolds which admit fixed point free circle actions. The first result implies that the torsion in the second homology and the second Stiefel-Whitney class have to satisfy strong restrictions. We then show that for simply connected 5-manifolds these restrictions are necessary and sufficient.     

Finite type invariants of cyclic branched covers

Given a knot in an integer homology sphere, one can construct a family of closed 3-manifolds (parameterized by the positive integers), namely the cyclic branched coverings of the knot. In this paper, we give a formula for the Casson-Walker invariants of these 3-manifolds in terms of residues of a rational function (which measures the 2-loop part of the Kontsevich integral of a knot) and the signature function of the knot. Our main result actually computes the LMO invariant of cyclic branched covers in terms of a rational invariant of the knot and its signature function.     

Homologically versus homotopically area minimizing surfaces in 3-manifolds

We construct a Riemannian metric on the 3-torus such that no closed surface minimizing area in its homology class is incompressible, i.e., each such surface is of genus greater than one. In particular, for such a Riemannian metric, the homotopically area minimizing 2-tori constructed in [5] do not minimize area in their homology classes. The example is easily generalized to arbitrary 3-manifolds. The constructed Riemannian metric can be chosen to be conformally equivalent to any arbitrary given one. Received September 4, 1998 / Accepted October 23, 1998     

Closed transversals and the genus of closed leaves in foliated 3-manifolds

The classical local theory of integrable 2-plane fields in 3-space leads to interesting qualitative questions about the global properties of solutions surface (i.e., leaves of a foliation) on 3-manifolds. It is now known that foliations admitting a closed leaf of suitably high genus abound on all closed or orientable 3-manifolds that are not rational homology spheres (S. Goodman, Proc. Nat. Acad. Sci. U.S.A.71 (1974), 4414–4415), and this leads to natural questions about the “positions” of such leaves relative to the rest of the foliation. One such question, suggested by Goodman's theorem on closed transversals (S. Goodman, ibid.), is considered here.     

Generalised Fibonacci manifolds

Fibonacci manifolds have a hyperbolic structure which may be defined via Fibonacci numbers. Using related sequences of Lucas numbers, other 3-manifolds are constructed, their geometric structures determined, and a curious relationship between the homology and the invariant trace-field examined.Supported by the Royal Society.     

Some examples of aspherical 4-manifolds that are homology 4-spheres

In this paper, Problem 4.17 on Kirby's problem list is solved by constructing infinitely many homotopy types of aspherical 4-manifolds that are homology 4-spheres.     

All flat three-manifolds appear as cusps of hyperbolic four-manifolds

There are ten diffeomorphism classes of compact, flat 3-manifolds. It has been conjectured that each of these occurs as the boundary of a 4-manifold whose interior admits a complete, hyperbolic structure of finite volume. This paper provides evidence in support of the conjecture. In particular, each diffeomorphism class of compact, flat 3-manifolds is shown to appear as one of the cusps of a complete, finite-volume, hyperbolic 4-manifold. This is done with a construction that uses special coverings of ³ by 3-balls. A further consequence of the construction is a finer result about the geometric structures which can be induced on cusps of complete, finite-volume, hyperbolic 4-manifolds. Using Mostow's Rigidity Theorem, one can show that not every flat structure occurs in this way. However, the fact that the flat structures induced on cusps of such 4-manifolds are dense in their respective moduli spaces follows from the construction.     

Two constructions of weight systems for invariants of knots in non-trivial 3-manifolds

A new family of weight systems of finite type knot invariants of any positive degree in orientable 3-manifolds with non-trivial first homology group is constructed. The principal part of the Casson invariant of knots in such manifolds is split into the sum of infinitely many independent weight systems. Examples of knots separated by corresponding invariants and not separated by any other known finite type invariants are presented.     

Boundary slopes of knots

The results in this paper show that simple connectivity of a 3-manifold is reflected in the behavior of essential surfaces in exteriors of knots in the manifold. A corollary of the main theorem is that any non-trivial knot, with irreducible complement, in a homotopy 3-sphere must have two boundary slopes that differ by at least 2. This statement is false for knots in a homology 3-sphere. The main theorem itself applies more generally to knots in closed orientable 3-manifolds with cyclic fundamental group. Received: January 20, 1998.     

The first homology of the group of equivariant diffeomorphisms and its applications

Let V be a representation space of a finite group G. We determinethe group structure of the first homology of the equivariantdiffeomorphism group of V. Then we can apply it to the calculationof the first homology of the corresponding automorphism groupsof smooth orbifolds, compact Hausdorff foliations, codimensionone or two compact foliations and the locally free S¹-actionson 3-manifolds. Received November 5, 2007.     

Contact topology and holomorphic invariants via elementary combinatorics

In recent times a great amount of progress has been achieved in symplectic and contact geometry, leading to the development of powerful invariants of 3-manifolds such as Heegaard Floer homology and embedded contact homology. These invariants are based on holomorphic curves and moduli spaces, but in the simplest cases, some of their structure reduces to some elementary combinatorics and algebra which may be of interest in its own right. In this note, which is essentially a light-hearted exposition of some previous work of the author, we give a brief introduction to some of the ideas of contact topology and holomorphic curves, discuss some of these elementary results, and indicate how they arise from holomorphic invariants.     

The Neumann-Siebenmann invariant and Seifert surgery

We discuss some relations between the invariant originated in Fukumoto-Furuta and the Neumann-Siebenmann invariant for the Seifert rational homology 3-spheres. We give certain constraints on Seifert 3-manifolds to be obtained by surgery on knots in homology 3-spheres in terms of these invariants.Mathematics Subject Classification (2000): 57M27, 57N13, 57N10Dedicated to Professor Yukio Matsumoto for his 60^th birthday     

Some computations of stable twisted homology for mapping class groups

Abstract

In this paper, we deal with stable homology computations with twisted coefficients for mapping class groups of surfaces and of 3-manifolds, automorphism groups of free groups with boundaries and automorphism groups of certain right-angled Artin groups. On the one hand, the computations are led using semidirect product structures arising naturally from these groups. On the other hand, we compute the stable homology with twisted coefficients by FI-modules. This notably uses a decomposition result of the stable homology with twisted coefficients for pre-braided monoidal categories proved in this paper.

Communicated by Jason P. Bell     

On fibering and splitting of 5-manifolds over the circle

Our main result is a generalization of Cappell's 5-dimensional splitting theorem. As an application, we analyze, up to internal s-cobordism, the smoothable splitting and fibering problems for certain 5-manifolds mapping to the circle. For example, these maps may have homotopy fibers which are in the class of finite connected sums of certain geometric 4-manifolds. Most of these homotopy fibers have non-vanishing second mod 2 homology and have fundamental groups of exponential growth, which are not known to be tractable by Freedman–Quinn topological surgery. Indeed, our key technique is topological cobordism, which may not be the trace of surgeries.     

二维流形上连续流的一个整体性质

本文研究闭二维流（闭曲面）上的连续流，证明了正半轨线ω极限集的一个世质，其中定理１是平面定性理论小ｐｏｉｎｃａｒｅ－Ｂｅｎｄｉｘｓｏｎ定理对二维流形的推广。     

On fibering and splitting of 5-manifolds over the circle

Our main result is a generalization of Cappell's 5-dimensional splitting theorem. As an application, we analyze, up to internal s-cobordism, the smoothable splitting and fibering problems for certain 5-manifolds mapping to the circle. For example, these maps may have homotopy fibers which are in the class of finite connected sums of certain geometric 4-manifolds. Most of these homotopy fibers have non-vanishing second mod 2 homology and have fundamental groups of exponential growth, which are not known to be tractable by Freedman-Quinn topological surgery. Indeed, our key technique is topological cobordism, which may not be the trace of surgeries.     

Small Exotic 4-Manifolds with Formula

We construct an infinite family of simply connected, pairwisenondiffeomorphic 4-manifolds, all homeomorphic to . Similar ideas provide examples of 4-manifolds with, , vanishing first homology and nontrivial Seiberg–Witteninvariants. 2000 Mathematics Subject Classification 57R55, 57R57.