Thesis advisor: Julia Elisenda Grigsby / Thesis advisor: David Treumann / In 2010, Seidel and Smith used their localization framework for Floer homologies to prove a Smith-type rank inequality for the symplectic Khovanov homology of 2-periodic links in the 3-sphere. Hendricks later used similar geometric techniques to prove analogous rank inequalities for the knot Floer homology of 2-periodic links. We use combinatorial and space-level techniques to prove analogous Smith-type inequalities for various flavors of Khovanov homology for periodic links in the 3-sphere of any prime periodicity. First, we prove a graded rank inequality for the annular Khovanov homology of 2-periodic links by showing grading obstructions to longer differentials in a localization spectral sequence. We remark that the same method can be extended to p-periodic links. Second, in joint work with Matthew Stoffregen, we construct a Z/p-equivariant stable homotopy type for odd and even, annular and non-annular Khovanov homologies, using Lawson, Lipshitz, and Sarkar's Burnside functor construction of a Khovanov stable homotopy type. Then, we identify the fixed-point sets and apply a version of the classical Smith inequality to obtain spectral sequences and rank inequalities relating the Khovanov homology of a periodic link with the annular Khovanov homology of the quotient link. As a corollary, we recover a rank inequality for Khovanov homology conjectured by Seidel and Smith's work on localization and symplectic Khovanov homology. / Thesis (PhD) — Boston College, 2019. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Mathematics.

In this work, we prove that the set of link-homotopy classes of generalized string links over a closed, connected and orientable surface M of genus g ≥ 1 form a group, denoted by Bn(M) and we find a presentation for it. Moreover, we prove that its normal subgroup PBnn(M), namely, the homotopy string links over M, is bi-orderable. These results extend results proved by Juan GonzalezMeneses in [GM], [GM2] and Ekaterina Yurasovskaya in [Y], respectively. Also, we obtain an exact sequence for link-homotopy braid groups, which is an extension of [Go, Theorem 1]. / Sem resumo

Em Artin (1925), Artin introduziu o estudo do grupo de tranças, o qual está intimamente relacionado ao estudo de nós e enlaçamentos. Em seu outro artigo Theory of Braids Artin (1947), ele questionou se as noções de isotopia e homotopia de tranças são as mesmas ou diferentes. Tal questão foi respondida muito mais tarde em Goldsmith (1974), onde a autora apresenta um exemplo de trança que é homotópica à trança trivial mas não é equivalente à trança trivial, caracterizando, além disso, o grupo de classes de homotopia de tranças puras no disco como um certo quociente do grupo de tranças puras original. Uma área de pesquisa mais recente nesta teoria é o estudo da ordenação destes grupos de tranças. Em Habegger e Lin (1990) os autores mostram que o grupo de classes de homotopia de tranças puras no disco é nilpotente e livre de torção. Resulta que ele é bi-ordenado. Em Yurasovskaya (2008) a autora fornece uma ordem explícita e calculável para este grupo. Neste trabalho discutiremos e apresentaremos os principais resultados neste contexto. / In Artin (1925), Artin introduced the study of braid groups, which is closely related to the study of knots and links. In his other paper Theory of Braids Artin (1947), he asked if the notions of isotopy and homotopy of braids are different or the same. Such question was answered much later in Goldsmith (1974), where the author presents an example of braid that is homotopic to the trivial braid, but it is not equivalent to the trivial braid, characterizing, beyond that, the group of homotopy classes of braids as an certain quotient of the original braid group. One more recent research area on this theory is the study of ordenation of braid groups. In Habegger e Lin (1990) the authors show that the homotopy group classes of pure braids is nilpotent and torsion free. It follows that it is bi-orderable. In Yurasovskaya (2008) the author provides one explicit and evaluable order for this group. In this work, we will discuss and present the main results involved on this context.

by Luk Wai Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 44-45). / ABSTRACT --- p.i / ACKNOWLEDGMENTS --- p.ii / Chapter CHAPTER 1. --- INTRODUCTION --- p.1 / Chapter CHAPTER 2. --- DRAWBACKS OF CLASSICAL THEORY --- p.4 / Chapter 2.1 --- Review of Sequential Iterative Methods --- p.4 / Chapter 2.2 --- Visualization Techniques --- p.8 / Chapter 2.3 --- Review of Deflation --- p.10 / Chapter CHAPTER 3. --- THE IMPROVEMENT OF THE ABERTH METHOD --- p.11 / Chapter 3.1 --- The Durand-Kerner method and the Aberth method --- p.11 / Chapter 3.2 --- The generalized Aberth method --- p.13 / Chapter 3.3 --- The modified Aberth Method for multiple-zero --- p.13 / Chapter 3.4 --- Choosing the initial approximations --- p.15 / Chapter 3.5 --- Multiplicity estimation --- p.16 / Chapter CHAPTER 4. --- THE HIGHER-ORDER ITERATIVE METHODS --- p.18 / Chapter 4.1 --- Introduction --- p.18 / Chapter 4.2 --- Convergence analysis --- p.20 / Chapter 4.3 --- Numerical Results --- p.28 / Chapter CHAPTER 5. --- PARALLEL DEFLATION --- p.32 / Chapter 5.1 --- The Algorithm --- p.32 / Chapter 5.2 --- The Problem of Zero Component --- p.34 / Chapter 5.3 --- The Problem of Round-off Error --- p.35 / Chapter CHAPTER 6. --- HOMOTOPY ALGORITHM --- p.36 / Chapter 6.1 --- Introduction --- p.36 / Chapter 6.2 --- Choosing Q(z) --- p.37 / Chapter 6.3 --- The arclength continuation method --- p.38 / Chapter 6.4 --- The bifurcation problem --- p.40 / Chapter 6.5 --- The suggested improvement --- p.41 / Chapter CHAPTER 7. --- CONCLUSION --- p.42 / REFERENCES --- p.44 / APPENDIX A. PROGRAM LISTING --- p.A-l / APPENDIX B. COLOR PLATES --- p.B-l

by Kwok, Wong-chuen Tony. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves [85-86]). / Acknowledgement / Abstract / Chapter I --- Laguerre's Method in Polynomial Zero-finding / Chapter 1 --- Background --- p.1 / Chapter 2 --- Introduction and Problems of Laguerre´ةs Method --- p.3 / Chapter 2.1 --- Laguerre´ةs Method in Symmetrie-Cluster Problem / Chapter 2.2 --- Cyclic Behaviour / Chapter 2.3 --- Supercluster Problem / Chapter 3 --- Proposed Enhancement to Laguerre 's Method --- p.9 / Chapter 3.1 --- Analysis of Adding a Zero or Pole / Chapter 3.2 --- Proposed Algorithm / Chapter 4 --- Conclusion --- p.17 / Chapter II --- Homotopy Methods applied to Polynomial Zero-finding / Chapter 1 --- Introduction --- p.18 / Chapter 2 --- Overcoming Bifurcation --- p.22 / Chapter 3 --- Comparison of Homotopy Algorithms --- p.27 / Chapter 4 --- Conclusion --- p.29 / Appendices / Chapter I --- Laguerre's Method in Polynomial Zero-finding / Chapter 0 --- Naming of Testing Polynomials / Chapter 1 --- Finding All Zeros using Proposed Laguerre's Method / Chapter 2 --- Experiments: Selected Pictures of Comparison of Proposed Strategy with Other Strategy / Chapter 3 --- Experiments: Tables of Comparison of Proposed Strategy with Other Strategy / Chapter 4 --- Distance Colorations and Target Colorations / Chapter II --- Homotopy Methods applied to Polynomial Zero-finding / Chapter 1 --- Comparison of Algorithms using Homotopy Method / Chapter 2 --- Experiments: Selected Pictorial Comparison / Chapter III --- An Example Demonstrating Effect of Round-off Errors References

Non-convex optimization of deep neural networks is a well-researched problem. We present a novel application of continuation methods for deep learning optimization that can potentially arrive at a better solution. In our method, we first decompose the original optimization problem into a sequence of problems using a homotopy method. To achieve this in neural networks, we derive the Continuation(C)- Activation function. First, C-Activation is a homotopic formulation of existing activation functions such as Sigmoid, ReLU or Tanh. Second, we apply a method which is standard in the parameter continuation domain, but to the best of our knowledge, novel to the deep learning domain. In particular, we use Natural Parameter Continuation with Secant approximation(NPCS), an effective training strategy that may find a superior local minimum for a non-convex optimization problem. Additionally, we extend our work on Step-up GANs, a data continuation approach, by deriving a method called Continuous(C)-SMOTE which is an extension of standard oversampling algorithms. We demonstrate the improvements made by our methods and establish a categorization of recent work done on continuation methods in the context of deep learning.

This paper introduces the background concepts necessary to develop a detailed proof of a theorem by Ralph H. Fox which states that two topological spaces are the same homotopy type if and only if both are deformation retracts of a third space, the mapping cylinder. The concepts of homotopy and deformation are introduced in chapter 2, and retraction and deformation retract are defined in chapter 3. Chapter 4 develops the idea of the mapping cylinder, and the proof is completed. Three special cases are examined in chapter 5.

Recent work of Bambozzi, Ben-Bassat, and Kremnitzer suggests that derived analytic geometry over a valued field k can be modelled as geometry relative to the quasi-abelian category of Banach spaces, or rather its completion Ind(Ban_k). In this thesis we develop a robust theory of homotopical algebra in Ch(E) for E any sufficiently 'nice' quasi-abelian, or even exact, category. Firstly we provide sufficient conditions on weakly idempotent complete exact categories E such that various categories of chain complexes in E are equipped with projective model structures. In particular we show that as soon as E has enough projectives, the category Ch₊(E) of bounded below complexes is equipped with a projective model structure. In the case that E also admits all kernels we show that it is also true of Ch≥0(E), and that a generalisation of the Dold-Kan correspondence holds. Supplementing the existence of kernels with a condition on the existence and exactness of certain direct limit functors guarantees that the category of unbounded chain complexes Ch(E) also admits a projective model structure. When E is monoidal we also examine when these model structures are monoidal. We then develop the homotopy theory of algebras in Ch(E). In particular we show, under very general conditions, that categories of operadic algebras in Ch(E) can be equipped with transferred model structures. Specialising to quasi-abelian categories we prove our main theorem, which is a vast generalisation of Koszul duality. We conclude by defining analytic extensions of the Koszul dual of a Lie algebra in Ind(Ban_k).

Building on the work of Conrad Plaut and Valera Berestovskii regarding uniform spaces and the covering spectrum of Christina Sormani and Guofang Wei developed for geodesic spaces, the author defines and develops discrete homotopy theory for metric spaces, which can be thought of as a discrete analog of classical path-homotopy and covering space theory. Given a metric space, X, this leads to the construction of a collection of covering spaces of X - and corresponding covering groups - parameterized by the positive real numbers, which we call the [epsilon]-covers and the [epsilon]-groups. These covers and groups evolve dynamically as the parameter decreases, changing topological type at specific parameter values which depend on the topology and local geometry of X. This leads to the definition of a critical spectrum for metric spaces, which is the set of all values at which the topological type of the covers change. Several results are proved regarding the critical spectrum and its connections to topology and local geometry, particularly in the context of geodesic spaces, refinable spaces, and Gromov-Hausdorff limits of compact metric spaces. We investigate the relationship between the critical spectrum and covering spectrum in the case when X is geodesic, connections between the geometry of the [epsilon]-groups and the metric and topological structure of the [epsilon]-covers, as well as the behavior of the [epsilon]-covers and critical values under Gromov-Hausdorff convergence.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 79-80).