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Geometric Analysis of Shapes and Its Application to Medical Image Analysis
Geometric Analysis of Shapes and Its application to Medical Image Analysis by Anirban Mukhopadhyay (Under the DIRECTION of Suchendra M. Bhandarkar) Abstract Geometric analysis of shapes plays an important role in the way the visual world is per- ceived by modern computers. To this end, low-level geometric features provide most obvious and important cues towards understanding the visual scene. A novel intrinsic geometric sur- face descriptor, termed as the Geodesic Field Estimate (GFE) is proposed. Also proposed is a parallel algorithm, well suited for implementation on Graphics Processing Units, for efficient computation of the shortest geodesic paths. Another low level geometric descriptor, termed as the Biharmonic Density Estimate, is proposed to provide an intrinsic geometric scale space signature for multiscale surface feature-based representation of deformable 3D shapes. The computer vision and graphics communities rely on mid-level geometric understanding as well to analyze a scene. Symmetry detection and partial shape matching play an important role as mid-level cues. A comprehensive framework for detection and characterization of partial intrinsic symmetry over 3D shapes is proposed. To identify prominent overlapping symmetric regions, the proposed framework is decoupled into Correspondence Space Voting followed by Transformation Space Mapping procedure. Moreover, a novel multi-criteria optimization framework for matching of partially visible shapes in multiple images using joint geometric embedding is also proposed. The ultimate goal of geometric shape analysis is to resolve high level applications of modern world. This dissertation has focused on three different application scenarios. In the first scenario, a novel approach for the analysis of the non-rigid Left Ventricular (LV) endocardial surface from Multi-Detector CT images, using a generalized isometry-invariant Bag-of-Features (BoF) descriptor, is proposed and implemented. -
[Math.DG] 1 Feb 2002
The BIC of a conical fibration. Martintxo Saralegi-Aranguren∗ Robert Wolak† Universit´ed’Artois Uniwersytet Jagiellonski November 14, 2018 Abstract In the paper we introduce the notions of a singular fibration and a singular Seifert fi- bration. These notions are natural generalizations of the notion of a locally trivial fibration to the category of stratified pseudomanifolds. For singular foliations defined by such fibra- tions we prove a de Rham type theorem for the basic intersection cohomology introduced the authors in a recent paper. One of important examples of such a structure is the natural projection onto the leaf space for the singular Riemannian foliation defined by an action of a compact Lie group on a compact smooth manifold. The failure of the Poincar´eduality for the homology and cohomology of some singular spaces led Goresky and MacPherson to introduce a new homology theory called intersection homology which took into account the properties of the singularities of the considered space (cf. [10]). This homology is defined for stratified pseudomanifolds. The initial idea was generalized in several ways. The theories of simplicial and singular homologies were developed as well as weaker notions of the perversity were proposed (cf. [11, 12]). Several versions of the Poincar´eduality were proved taking into account the notion of dual perversities. Finally, the deRham intersection cohomology was defined by Goresky and MacPherson for Thom-Mather stratified spaces. The first written reference is the paper by J.L. Brylinski, cf. [6]. This led to the search for the ”de Rham - type” theorem for the intersection cohomology. The first author in his thesis and several subsequent publications, (cf. -
Arxiv:Math/9201256V1 [Math.RT] 1 Jan 1992 Naso Lblaayi N Geometry and Vol
Annals of Global Analysis and Geometry Vol. 8, No. 3 (1990), 299–313 THE MOMENT MAPPING FOR UNITARY REPRESENTATIONS Peter W. Michor Institut f¨ur Mathematik der Universit¨at Wien, Austria Abstract. For any unitary representation of an arbitrary Lie group I construct a moment mapping from the space of smooth vectors of the representation into the dual of the Lie algebra. This moment mapping is equivariant and smooth. For the space of analytic vectors the same construction is possible and leads to a real analytic moment mapping. Table of contents 1.Introduction . .. .. .. .. .. .. .. .. .. .. 1 2.Calculusofsmoothmappings . 2 3.Calculusofholomorphicmappings . 5 4.Calculusofrealanalyticmappings . 6 5.TheSpaceofSmoothVectors . 7 6.Themodelforthemomentmapping . 8 7. Hamiltonian Mechanics on H∞ .................... 9 8. The moment mapping for a unitary representation . .... 11 9.Therealanalyticmomentmapping . 13 1. Introduction arXiv:math/9201256v1 [math.RT] 1 Jan 1992 With the help of the cartesian closed calculus for smooth mappings as explained in [F-K] we can show, that for any Lie group and for any unitary representation its restriction to the space of smooth vectors is smooth. The imaginary part of the hermitian inner product restricts to a ”weak” symplectic structure on the vector space of smooth vectors. This gives rise to the Poisson bracket on a suitably chosen space of smooth functions on the space of smooth vectors. The derivative of the representation on the space of smooth vectors is a symplectic action of the Lie algebra, which can be lifted to a Hamiltonian action, i.e. a Lie algebra homomorphism from the Lie algebra into the function space with the Poisson bracket. -
Symmetric and Pseudoisotropic Distributions: -Fund Separation
Hindawi Publishing Corporation Journal of Probability and Statistics Volume 2015, Article ID 235452, 11 pages http://dx.doi.org/10.1155/2015/235452 Research Article Portfolio Theory for -Symmetric and Pseudoisotropic Distributions: -Fund Separation and the CAPM Nils Chr. Framstad DepartmentofEconomics,UniversityofOslo,P.O.Box1095,Blindern,0317Oslo,Norway Correspondence should be addressed to Nils Chr. Framstad; [email protected] Received 30 June 2015; Revised 6 October 2015; Accepted 12 October 2015 Academic Editor: Chunsheng Ma Copyright © 2015 Nils Chr. Framstad. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The shifted pseudoisotropic multivariate distributions are shown to satisfy Ross’ stochastic dominance criterion for two-fund monetary separation in the case with risk-free investment opportunity and furthermore to admit the Capital Asset Pricing Model under an embedding in L condition if 1<≤2, with the betas given in an explicit form. For the -symmetric subclass, the market without risk-free investment opportunity admits 2-fund separation if = 1+1/(2−1), ∈N, generalizing the classical elliptical case =1, and we also give the precise number of funds needed, from which it follows that we cannot, except degenerate cases, have a CAPM without risk-free opportunity. For the symmetric stable subclass, the index of stability is only of secondary interest, and several common restrictions in terms of that index can be weakened by replacing it by the (no smaller) indices of symmetry/of embedding. Finally, dynamic models with intermediate consumption inherit the separation properties of the static models. -
Paracompactness and C2 -Paracompactness
Turkish Journal of Mathematics Turk J Math (2019) 43: 9 – 20 http://journals.tubitak.gov.tr/math/ © TÜBİTAK Research Article doi:10.3906/mat-1804-54 C -Paracompactness and C2 -paracompactness Maha Mohammed SAEED∗,, Lutfi KALANTAN,, Hala ALZUMI, Department of Mathematics, King Abdulaziz University, Jeddah, Saudi Arabia Received: 17.04.2018 • Accepted/Published Online: 29.08.2018 • Final Version: 18.01.2019 Abstract: A topological space X is called C -paracompact if there exist a paracompact space Y and a bijective function f : X −! Y such that the restriction fjA : A −! f(A) is a homeomorphism for each compact subspace A ⊆ X .A topological space X is called C2 -paracompact if there exist a Hausdorff paracompact space Y and a bijective function f : X −! Y such that the restriction fjA : A −! f(A) is a homeomorphism for each compact subspace A ⊆ X . We investigate these two properties and produce some examples to illustrate the relationship between them and C -normality, minimal Hausdorff, and other properties. Key words: Normal, paracompact, C -paracompact, C2 -paracompact, C -normal, epinormal, mildly normal, minimal Hausdorff, Fréchet, Urysohn 1. Introduction We introduce two new topological properties, C -paracompactness and C2 -paracompactness. They were defined by Arhangel’skiĭ. The purpose of this paper is to investigate these two properties. Throughout this paper, we denote an ordered pair by hx; yi, the set of positive integers by N, the rational numbers by Q, the irrational numbers by P, and the set of real numbers by R. T2 denotes the Hausdorff property. A T4 space is a T1 normal space and a Tychonoff space (T 1 ) is a T1 completely regular space. -
Karen Keskulla Uhlenbeck
2019 The Norwegian Academy of Science and Letters has decided to award the Abel Prize for 2019 to Karen Keskulla Uhlenbeck University of Texas at Austin “for her pioneering achievements in geometric partial differential equations, gauge theory and integrable systems, and for the fundamental impact of her work on analysis, geometry and mathematical physics.” Karen Keskulla Uhlenbeck is a founder of modern by earlier work of Morse, guarantees existence of Geometric Analysis. Her perspective has permeated minimisers of geometric functionals and is successful the field and led to some of the most dramatic in the case of 1-dimensional domains, such as advances in mathematics in the last 40 years. closed geodesics. Geometric analysis is a field of mathematics where Uhlenbeck realised that the condition of Palais— techniques of analysis and differential equations are Smale fails in the case of surfaces due to topological interwoven with the study of geometrical and reasons. The papers of Uhlenbeck, co-authored with topological problems. Specifically, one studies Sacks, on the energy functional for maps of surfaces objects such as curves, surfaces, connections and into a Riemannian manifold, have been extremely fields which are critical points of functionals influential and describe in detail what happens when representing geometric quantities such as energy the Palais-Smale condition is violated. A minimising and volume. For example, minimal surfaces are sequence of mappings converges outside a finite set critical points of the area and harmonic maps are of singular points and by using rescaling arguments, critical points of the Dirichlet energy. Uhlenbeck’s they describe the behaviour near the singularities major contributions include foundational results on as bubbles or instantons, which are the standard minimal surfaces and harmonic maps, Yang-Mills solutions of the minimising map from the 2-sphere to theory, and integrable systems. -
Base-Paracompact Spaces
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Topology and its Applications 128 (2003) 145–156 www.elsevier.com/locate/topol Base-paracompact spaces John E. Porter Department of Mathematics and Statistics, Faculty Hall Room 6C, Murray State University, Murray, KY 42071-3341, USA Received 14 June 2001; received in revised form 21 March 2002 Abstract A topological space is said to be totally paracompact if every open base of it has a locally finite subcover. It turns out this property is very restrictive. In fact, the irrationals are not totally paracompact. Here we give a generalization, base-paracompact, to the notion of totally paracompactness, and study which paracompact spaces satisfy this generalization. 2002 Elsevier Science B.V. All rights reserved. Keywords: Paracompact; Base-paracompact; Totally paracompact 1. Introduction A topological space X is paracompact if every open cover of X has a locally finite open refinement. A topological space is said to be totally paracompact if every open base of it has a locally finite subcover. Corson, McNinn, Michael, and Nagata announced [3] that the irrationals have a basis which does not have a locally finite subcover, and hence are not totally paracompact. Ford [6] was the first to give the definition of totally paracompact spaces. He used this property to show the equivalence of the small and large inductive dimension in metric spaces. Ford also showed paracompact, locally compact spaces are totally paracompact. Lelek [9] studied totally paracompact and totally metacompact separable metric spaces. He showed that these two properties are equivalent in separable metric spaces. -
Differential Geometry: Curvature and Holonomy Austin Christian
University of Texas at Tyler Scholar Works at UT Tyler Math Theses Math Spring 5-5-2015 Differential Geometry: Curvature and Holonomy Austin Christian Follow this and additional works at: https://scholarworks.uttyler.edu/math_grad Part of the Mathematics Commons Recommended Citation Christian, Austin, "Differential Geometry: Curvature and Holonomy" (2015). Math Theses. Paper 5. http://hdl.handle.net/10950/266 This Thesis is brought to you for free and open access by the Math at Scholar Works at UT Tyler. It has been accepted for inclusion in Math Theses by an authorized administrator of Scholar Works at UT Tyler. For more information, please contact [email protected]. DIFFERENTIAL GEOMETRY: CURVATURE AND HOLONOMY by AUSTIN CHRISTIAN A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Department of Mathematics David Milan, Ph.D., Committee Chair College of Arts and Sciences The University of Texas at Tyler May 2015 c Copyright by Austin Christian 2015 All rights reserved Acknowledgments There are a number of people that have contributed to this project, whether or not they were aware of their contribution. For taking me on as a student and learning differential geometry with me, I am deeply indebted to my advisor, David Milan. Without himself being a geometer, he has helped me to develop an invaluable intuition for the field, and the freedom he has afforded me to study things that I find interesting has given me ample room to grow. For introducing me to differential geometry in the first place, I owe a great deal of thanks to my undergraduate advisor, Robert Huff; our many fruitful conversations, mathematical and otherwise, con- tinue to affect my approach to mathematics. -
Convenient Vector Spaces, Convenient Manifolds and Differential Linear Logic
Convenient Vector Spaces, Convenient Manifolds and Differential Linear Logic Richard Blute University of Ottawa ongoing discussions with Geoff Crutwell, Thomas Ehrhard, Alex Hoffnung, Christine Tasson June 20, 2011 Richard Blute Convenient Vector Spaces, Convenient Manifolds and Differential Linear Logic Goals Develop a theory of (smooth) manifolds based on differential linear logic. Or perhaps develop a differential linear logic based on manifolds. Convenient vector spaces were recently shown to be a model. There is a well-developed theory of convenient manifolds, including infinite-dimensional manifolds. Convenient manifolds reveal additional structure not seen in finite dimensions. In particular, the notion of tangent space is much more complex. Synthetic differential geometry should also provide information. Convenient vector spaces embed into an extremely good model. Richard Blute Convenient Vector Spaces, Convenient Manifolds and Differential Linear Logic Convenient vector spaces (Fr¨olicher,Kriegl) Definition A vector space is locally convex if it is equipped with a topology such that each point has a neighborhood basis of convex sets, and addition and scalar multiplication are continuous. Locally convex spaces are the most well-behaved topological vector spaces, and most studied in functional analysis. Note that in any topological vector space, one can take limits and hence talk about derivatives of curves. A curve is smooth if it has derivatives of all orders. The analogue of Cauchy sequences in locally convex spaces are called Mackey-Cauchy sequences. The convergence of Mackey-Cauchy sequences implies the convergence of all Mackey-Cauchy nets. The following is taken from a long list of equivalences. Richard Blute Convenient Vector Spaces, Convenient Manifolds and Differential Linear Logic Convenient vector spaces II: Definition Theorem Let E be a locally convex vector space. -
Grothendieck Spaces with the Dunford–Pettis Property
GROTHENDIECK SPACES WITH THE DUNFORD–PETTIS PROPERTY ANGELA A. ALBANESE*, JOSÉ BONET+ AND WERNER J. RICKER Abstract. Banach spaces which are Grothendieck spaces with the Dunford– Pettis property (briefly, GDP) are classical. A systematic treatment of GDP– Fréchet spaces occurs in [12]. This investigation is continued here for locally convex Hausdorff spaces. The product and (most) inductive limits of GDP– space are again GDP–spaces. Also, every complete injective space is a GDP– space. For p ∈ {0} ∪ [1, ∞) it is shown that the classical co–echelon spaces kp(V ) and Kp(V ) are GDP–spaces if and only if they are Montel. On the other hand, K∞(V ) is always a GDP–space and k∞(V ) is a GDP–space whenever its (Fréchet) predual, i.e., the Köthe echelon space λ1(A), is distinguished. 1. Introduction. Grothendieck spaces with the Dunford–Pettis property (briefly, GDP) play a prominent role in the theory of Banach spaces and vector measures; see Ch.VI of [17], especially the Notes and Remarks, and [18]. Known examples include L∞, ∞ ∞ H (D), injective Banach spaces (e.g. ` ) and certain C(K) spaces. D. Dean showed in [14] that a GDP–space does not admit any Schauder decomposition; see also [26, Corollary 8]. This has serious consequences for spectral measures in such spaces, [31]. For non–normable spaces the situation changes dramatically. Every Fréchet Montel space X is a GDP–space, [12, Remark 2.2]. Other than Montel spaces, the only known non–normable Fréchet space which is a GDP–space is the Köthe echelon space λ∞(A), for an arbitrary Köthe matrix A, [12, Proposition 3.1]. -
Iasinstitute for Advanced Study
IAInsti tSute for Advanced Study Faculty and Members 2012–2013 Contents Mission and History . 2 School of Historical Studies . 4 School of Mathematics . 21 School of Natural Sciences . 45 School of Social Science . 62 Program in Interdisciplinary Studies . 72 Director’s Visitors . 74 Artist-in-Residence Program . 75 Trustees and Officers of the Board and of the Corporation . 76 Administration . 78 Past Directors and Faculty . 80 Inde x . 81 Information contained herein is current as of September 24, 2012. Mission and History The Institute for Advanced Study is one of the world’s leading centers for theoretical research and intellectual inquiry. The Institute exists to encourage and support fundamental research in the sciences and human - ities—the original, often speculative thinking that produces advances in knowledge that change the way we understand the world. It provides for the mentoring of scholars by Faculty, and it offers all who work there the freedom to undertake research that will make significant contributions in any of the broad range of fields in the sciences and humanities studied at the Institute. Y R Founded in 1930 by Louis Bamberger and his sister Caroline Bamberger O Fuld, the Institute was established through the vision of founding T S Director Abraham Flexner. Past Faculty have included Albert Einstein, I H who arrived in 1933 and remained at the Institute until his death in 1955, and other distinguished scientists and scholars such as Kurt Gödel, George F. D N Kennan, Erwin Panofsky, Homer A. Thompson, John von Neumann, and A Hermann Weyl. N O Abraham Flexner was succeeded as Director in 1939 by Frank Aydelotte, I S followed by J. -
Semilinear Wave Equations on Asymptotically De Sitter, Kerr-De Sitter and Minkowski Spacetimes
SEMILINEAR WAVE EQUATIONS ON ASYMPTOTICALLY DE SITTER, KERR-DE SITTER AND MINKOWSKI SPACETIMES PETER HINTZ AND ANDRAS VASY Abstract. In this paper we show the small data solvability of suitable semi- linear wave and Klein-Gordon equations on geometric classes of spaces, which include so-called asymptotically de Sitter and Kerr-de Sitter spaces, as well as asymptotically Minkowski spaces. These spaces allow general infinities, called conformal infinity in the asymptotically de Sitter setting; the Minkowski type setting is that of non-trapping Lorentzian scattering metrics introduced by Baskin, Vasy and Wunsch. Our results are obtained by showing the global Fredholm property, and indeed invertibility, of the underlying linear operator on suitable L2-based function spaces, which also possess appropriate algebra or more complicated multiplicative properties. The linear framework is based on the b-analysis, in the sense of Melrose, introduced in this context by Vasy to describe the asymptotic behavior of solutions of linear equations. An inter- esting feature of the analysis is that resonances, namely poles of the inverse of the Mellin transformed b-normal operator, which are `quantum' (not purely symbolic) objects, play an important role. 1. Introduction In this paper we consider semilinear wave equations in contexts such as asymp- totically de Sitter and Kerr-de Sitter spaces, as well as asymptotically Minkowski spaces. The word `asymptotically' here does not mean that the asymptotic behav- ior has to be that of exact de Sitter, etc., spaces, or even a perturbation of these at infinity; much more general infinities, that nonetheless possess a similar structure as far as the underlying analysis is concerned, are allowed.