Yiu, Fa Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 55-58). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.6 / Chapter 2 --- Elementary properties and notations of Hyperbolic space --- p.9 / Chapter 3 --- Poisson kernel and Conformal densities --- p.16 / Chapter 3.1 --- Poisson kernel --- p.17 / Chapter 3.2 --- Conformal densities --- p.19 / Chapter 4 --- Patterson construction and decomposition --- p.27 / Chapter 4.1 --- Patterson construction --- p.27 / Chapter 4.2 --- Patterson decomposition --- p.33 / Chapter 5 --- Bonahon surfaces and Grided surfaces --- p.39 / Chapter 5.1 --- Bonahon surfaces --- p.40 / Chapter 5.2 --- Grided surfaces --- p.46 / Chapter 6 --- Margulis number of Hyperbolic Manifolds --- p.51 / Margulis Number for Hypcrbolic 3-manifolds --- p.5 / Chapter 6.1 --- Gcomertrically finite groups --- p.51 / Chapter 6.2 --- Margulis number of Closed Hyperbolic Manifolds --- p.53 / Bibliography --- p.55

This thesis consists of three applications of Ranicki's algebraic theory of surgery to the topology of manifolds. The common theme is a decomposition of a global algebraic object into simple local pieces which models the decomposition of a global topological object into simple local pieces. Part I: Algebraic reconstruction of 4-manifolds. We extend the product and glueing constructions for symmetric Poincaré complexes, pairs and triads to a thickening construction for a symmetric Poincaré representation of a quiver. Gay and Kirby showed that, subject to certain conditions, the fold curves and fibres of a Morse 2-function F : M4 → Ʃ 2 determine a quiver of manifold and glueing data which allows one to reconstruct M and F up to diffeomorphism. The Gay-Kirby method of reconstructing M glues the pre-images of disc neighbourhoods of cusps and crossings with thickenings of regular fibres and thickenings of cobordisms between regular fibres. We use our thickening construction for a symmetric Poincaré representation of a quiver to give an algebraic analogue of the Gay-Kirby result to reconstruct the symmetric Poincaré complex (C(M); ϕ M) of M from a Morse 2-function. Part II: The L-theory of triangular matrix rings. We construct a chain duality on the category of left modules over a triangular matrix ring A = (A1;A2;B) where A1;A2 are rings with involution and B is an (A1;A2)-bimodule. We describe the resulting L-theory of A and relate it to the L-theory of A1;A2 and to the change of rings morphism B ⊗A2 − : A2-Mod → A1-Mod. By examining algebraic surgery over A we define a relative algebraic surgery operation on an (n+1)-dimensional symmetric Poincaré pair with data an (n+2)-dimensional triad. This gives an algebraic model for a half-surgery on a manifold with boundary. We then give an algebraic analogue of Borodzik, Némethi and Ranciki's half-handle decomposition of a relative manifold cobordism and show that every relative Poincaré cobordism is homotopy equivalent to a union of traces of elementary relative surgeries. Part III: Seifert matrices of braids with applications to isotopy and signatures. Let β be a braid with closure ^β a link. Collins developed an algorithm to find the Seifert matrix of the canonical Seifert surface Ʃ of ^ β constructed by Seifert's algorithm. Motivated by Collins' algorithm and a construction of Ghys, we define a 1-dimensional simplicial complex K(β) and a bilinear form λβ : C1(K(β);Z)×C1(K(β);Z) → Z[ 1/2 ] such that there is an inclusion K(β) ~ → Ʃ which is a homotopy equivalence inducing an isomorphism H1(Ʃ;Z) ≅ H1(K(β);Z) such that [λβ] : H1(K(β);Z) × H1(K(β);Z) → Z ⊂ Z[ 1/2 ] is the Seifert form of Ʃ. We show that this chain level model is additive under the concatenation of braids and then verify that this model is chain equivalent to Banchoff's combinatorial model for the linking number of two space polygons and Ranicki's surgery theoretic model for a chain level Seifert pairing. We then define the chain level Seifert pair (λβ; d β) of a braid β and equivalence relations, called A and Â-equivalence. Two n-strand braids are isotopic if and only if their chain level Seifert pairs are A-equivalent and this yields a universal representation of the braid group. Two n-strand braids have isotopic link closures in the solid torus D2 ×S1 if and only if their chain level Seifert pairs are  A-equivalent and this yields a representation of the braid group modulo conjugacy. We use the first representation to express the ω signature of a braid β in terms of the chain level Seifert pair (λ β; d β).

Suen, Chun Kit Anthony. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 89-92). / Abstracts in English and Chinese. / Abstract --- p.iii / Abstract --- p.iv / Acknowledgements --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Morse Homology --- p.5 / Chapter 2.1 --- Introduction --- p.5 / Chapter 2.2 --- Classical Morse Theory and Morse Functions --- p.5 / Chapter 2.3 --- Handlebody Decomposition for 3-manifold --- p.7 / Chapter 2.4 --- Stable manifold and Unstable manifold --- p.10 / Chapter 2.5 --- Trajectory flows and the Morse-Smale-Witten Complex --- p.11 / Chapter 3 --- Lagrangian Floer Homology --- p.22 / Chapter 3.1 --- Introduction --- p.22 / Chapter 3.2 --- Preliminaries on Symplectic Geometry --- p.23 / Chapter 3.2.1 --- Basic Definitions --- p.23 / Chapter 3.2.2 --- The Symplectic Group --- p.26 / Chapter 3.2.3 --- Maslov index for non-degenerate paths in Sp(2n) --- p.28 / Chapter 3.2.4 --- Maslov index - the analytic aspect --- p.35 / Chapter 3.3 --- Definition of Floer Homology --- p.37 / Chapter 3.4 --- Some Remarks --- p.41 / Chapter 4 --- Heegaard Floer Homology --- p.43 / Chapter 4.1 --- Introduction --- p.43 / Chapter 4.2 --- Basic Set-Up --- p.43 / Chapter 4.3 --- Topological Preliminaries --- p.44 / Chapter 4.3.1 --- Symmetric Product --- p.44 / Chapter 4.3.2 --- The Tori Tα and Tβ --- p.47 / Chapter 4.3.3 --- Intersection Points and Disks --- p.48 / Chapter 4.3.4 --- Domains --- p.52 / Chapter 4.3.5 --- Spinc Structures --- p.54 / Chapter 4.3.6 --- Holomorphic Disks and Maslov Index --- p.63 / Chapter 4.4 --- Definition of Heegaard Floer Homology --- p.65 / Chapter 4.4.1 --- The chain complex CF --- p.66 / Chapter 4.4.2 --- The chain complex CF∞ --- p.67 / Chapter 4.4.3 --- The chain complexes CF+ and CF- --- p.68 / Chapter 4.4.4 --- Some Remarks --- p.70 / Chapter 5 --- Examples and Applications --- p.72 / Chapter 5.1 --- Introduction --- p.72 / Chapter 5.2 --- The homology three-spheres --- p.72 / Chapter 5.2.1 --- The sphere S3 --- p.72 / Chapter 5.2.2 --- The Poincare sphere and the Brieskorn spheres --- p.74 / Chapter 5.2.3 --- Long exact surgery sequence and the absolutely graded Hee- gaard Floer homology --- p.78 / Chapter 5.3 --- More Application --- p.84 / Chapter 5.3.1 --- Knot Floer homology --- p.84 / Chapter 5.3.2 --- Invariants on 4-manifolds --- p.86 / Chapter 5.4 --- Further developments --- p.87 / Bibliography --- p.89

There is an algebra defined on a two dimensional manifold, known as the Skein algebra, which has as elements the simple closed curves of the manifold. Just like with numbers, there's a way to add, subtract and multiply elements. Unfortunately division is not allowed in the Skein algebra, which is why we introduced the notion of the Localized Skein Algebra, where we define a way to invert elements so that dividing is possible. These algebras have infinitely many elements, may not be commutative and in fact may have torsion, which makes them a hard object to study. This work is mainly centered in reducing these algebras to something more manageable. We have shown that for any space, its Localized Skein Algebra is a Frobenius extension of its Localized Character Ring, which means that any element of the algebra can be rewritten as a finite linear combination of a finite subset of basis elements, multiplied by elements that do commute. The importance of this result is that it solves this problem of noncommutativity, by rewriting anything that doesn't commute, as elements of a small set which can be controlled, along with elements that commute and behave nicely, making the Skein algebra far more manageable.

We de…ne a uniformity on a glued space under uniformly continuous attachment maps. If the component spaces are uniform coverable then the resulting glued space is uniform coverable. We consider examples including the glued uniformity on a …nite dimensional CW complex which is shown to be uniformly coverable. For one dimensional CWcomplexes, the resulting deck group is equivalent to the fundamental group. Other properties of the deck group are explored.

Un arrangement central A est un ensemble fini de sous-espaces vectoriels dans un espace vectoriel complexe V de dimension finie. L'espace topologique complémentaire M(A) est l'ensemble des points de V qui n'appartiennent à aucun des sous-espaces de A. Dans ce travail, nous étudions la topologie de l'espace M(A) du point de vue de l'homotopie rationnelle. L'outil clé qui a servi de départ à cette thèse est un modèle rationnel de M(A) qui s'avère relativement simple à manipuler. À l'aide de ce modèle, nous obtenons plusieurs résultats sur la topologie de M(A). Citons par exemple des formules de récursion qui permettent de calculer certains invariants topologiques, dont les nombres de Betti, une preuve du fait que la caractéristique d'Euler de l'espace M(A) est nulle ou encore une description des arrangements (vérifiant une condition technique) dont le complémentaire est un wedge rationnel de sphères. Enfin, les résultats principaux de cet ouvrage sont une caractérisation des arrangements dont le complémentaire a le type d'homotopie d'un produit de sphères, et la preuve du fait que si le complémentaire n'est pas un produit de sphères, alors son algèbre de Lie d'homotopie contient la sous-algèbre de Lie libre à deux générateurs.

In this thesis, we propose a high level design for connectivity visualization of OLSRbased MANET topology based on local topology databases available in an OLSR node. Two different scenarios are considered: a central (full view) topology from a command and control location, or a nodal (partial) view from an ad-hoc node. A simulation-based analysis is conducted to calculate total number of active links at a particular time in full and nodal topology views. Also the error rate of network topology discovery based on total undiscovered link both mobile and static scenario is considered and reported. We also come up with an analytical model to analyse the network bandwidth and overhead of using TC, HELLO and custom NIM message to evaluate the performance of centralized visualization to build full map of the network with respect to situational awareness system. This thesis also presents a multi-node, 2-dimensional, distributed technique for coarse (approximate) localization of the nodes in a tactical mobile ad hoc network. The objective of this work is to provide coarse localization information based on layer-3 connectivity information and a few anchor nodes or landmarks, and without using traditional methods such as signal strength, Time of Arrival (ToA) or distance information. We propose a localization algorithm based on a Force-directed method that will allow us to estimate the approximate location of each node based on network topology information from a local OLSR database. We assume the majority of nodes are not equipped with GPS and thus do not have their exact location information. In our proposed approach we make use of the possible existence of known landmarks as reference points to enhance the accuracy of localization. / UOIT

The first part of this thesis investigates the Gromov width of maximal dimensional coadjoint orbits of compact simple Lie groups. An upper bound for the Gromov width is provided for all compact simple Lie groups but only for those coadjoint orbits that satisfy a certain technical assumption, whereas the lower bound is proved only for groups of type A, but without the technical restriction. The two bounds use very different techniques: the proof of the upper bound uses more analytical tools, while the proof of the lower bound is more geometric. The second part of the thesis is a short report on a joint project with my supervisor, which was concerned with the relationship between two different definitions of orbifolds: one using Lie groupoids and the other involving diffeologies. The results are summarized in Chapter 5 of this text.

The first part of this thesis investigates the Gromov width of maximal dimensional coadjoint orbits of compact simple Lie groups. An upper bound for the Gromov width is provided for all compact simple Lie groups but only for those coadjoint orbits that satisfy a certain technical assumption, whereas the lower bound is proved only for groups of type A, but without the technical restriction. The two bounds use very different techniques: the proof of the upper bound uses more analytical tools, while the proof of the lower bound is more geometric. The second part of the thesis is a short report on a joint project with my supervisor, which was concerned with the relationship between two different definitions of orbifolds: one using Lie groupoids and the other involving diffeologies. The results are summarized in Chapter 5 of this text.

In his 1947 work "Theory of Braids" Emil Artin asked whether the braid group remained unchanged when one considered classes of braids under linkhomotopy, allowing each strand of a braid to pass through itself but not through other strands. We generalize Artin's question to string links over orientable surface M and show that under link-homotopy surface string links form a group PBn(M), which is isomorphic to a quotient of the surface pure braid group PBn(M). Surface braid groups and their properties are an area of active research by González-Meneses, Paris and Rolfsen, Goçalves and Guaschi, and our work explores the geometric and visual beauty of this subject. We compute a presentation of PBn(M) in terms of the generators and relations and discuss the orderability of the group in the case when the surface in question is a unit disk D.