Download or read book Weyl Groups and Birational Transformations among Minimal Models written by Kenji Matsuki and published by American Mathematical Soc.. This book was released on 1995 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we provide a unified way of looking at the apparently sporadic Weyl groups connected with the classical geometry of surfaces, namely those with 1) the rational double points, 2) the Picard groups of Del Pezzo surfaces, 3) the Kodaira-type degenerations of elliptic curves, and 4) the Picard-Lefschetz reflections of [italic]K3-surfaces, by putting them together into the picture of 3-dimensional birational geometry in the realm of the recently established Minimal Model Theory for 3-folds.

Download or read book Weyl Groups and Birational Transformations Among Minimal Models written by Kenji Matsuki and published by . This book was released on 1995 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Model Theory and Linear Extreme Points in the Numerical Radius Unit Ball written by Michael A. Dritschel and published by American Mathematical Soc.. This book was released on 1997 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: This memoir initiates a model theory-based study of the numerical radius norm. Guided by the abstract model theory of Jim Agler, the authors propose a decomposition for operators that is particularly useful in understanding their properties with respect to the numerical radius norm. Of the topics amenable to investigation with these tools, the following are presented: a complete description of the linear extreme points of the non-matrix (numerical radius) unit ball; several equivalent characterizations of matricial extremals in the unit ball, that is, those members which do not allow a nontrivial extension remaining in the unit ball; and applications to numerical ranges of matrices, including a complete parameterization of all matrices whose numerical ranges are closed disks.

Download or read book Compact Connected Lie Transformation Groups on Spheres with Low Cohomogeneity I written by Eldar Straume and published by American Mathematical Soc.. This book was released on 1996 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cohomogeneity of a transformation group ([italic capitals]G, X) is, by definition, the dimension of its orbit space, [italic]c = dim [italic capitals]X, G. By enlarging this simple numerical invariant, but suitably restricted, one gradually increases the complexity of orbit structures of transformation groups. This is a natural program for classical space forms, which traditionally constitute the first canonical family of testing spaces, due to their unique combination of topological simplicity and abundance in varieties of compact differentiable transformation groups.

Download or read book Compact Connected Lie Transformation Groups on Spheres with Low Cohomogeneity II written by Eldar Straume and published by American Mathematical Soc.. This book was released on 1997 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cohomogeneity of a transformation group ([italic capitals]G, X) is, by definition, the dimension of its orbit space, [italic]c = dim [italic capitals]X, G. We are concerned with the classification of differentiable compact connected Lie transformation groups on (homology) spheres, with [italic]c [less than or equal to symbol] 2, and the main results are summarized in five theorems, A, B, C, D, and E in part I. This paper is part II of the project, and addresses theorems D and E. D examines the orthogonal model from theorem A and orbit structures, while theorem E addresses the existence of "exotic" [italic capital]G-spheres.

Download or read book The Index Theorem for Minimal Surfaces of Higher Genus written by Friedrich Tomi and published by American Mathematical Soc.. This book was released on 1995 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we formulate and prove an index theorem for minimal surfaces of higher topological type spanning one boundary contour. Our techniques carry over to surfaces with several boundary contours as well as to unoriented surfaces.

Download or read book Complex Algebraic Threefolds written by Masayuki Kawakita and published by Cambridge University Press. This book was released on 2023-11-30 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed treatment of the explicit aspects of the birational geometry of algebraic threefolds arising from the minimal model program.

Download or read book L Functions for the Orthogonal Group written by David Ginzburg and published by American Mathematical Soc.. This book was released on 1997 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, the authors establish global Rankin Selberg integrals which determine the standard [italic capital]L function for the group [italic capitals]GL[subscript italic]r x [italic capital]Gʹ, where [italic capital]Gʹ is an isometry group of a nondegenerate symmetric form. The class of automorphic representations considered here is for any pair [capital Greek]Pi1 [otimes/dyadic/Kronecker/tensor product symbol] [capital Greek]Pi2 where [capital Greek]Pi1 is generic cuspidal for [italic capitals]GL[subscript italic]r([italic capital]A) and [capital Greek]Pi2 is cuspidal for [italic capital]Gʹ([italic capital]A). The construction of these [italic capital]L functions involves the use of certain new "models" of local representations; these models generalize the usual generic models. The authors also computer local unramified factors in a new way using geometric ideas.

Download or read book Some Connections between Isoperimetric and Sobolev type Inequalities written by Serguei Germanovich Bobkov and published by American Mathematical Soc.. This book was released on 1997 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: For Borel probability measures on metric spaces, this text studies the interplay between isoperimetric and Sobolev-type inequalities. In particular the question of finding optimal constants via isoperimetric quantities is explored. Also given are necessary and sufficient conditions for the equivalence between the extremality of some sets in the isoperimetric problem and the validity of some analytic inequalities. The book devotes much attention to: the probability distributions on the real line; the normalized Lebesgue measure on the Euclidean sheres; and the canonical Gaussian measure on the Euclidean space.

Download or read book Families of Curves in mathbb P 3 and Zeuthen s Problem written by Robin Hartshorne and published by American Mathematical Soc.. This book was released on 1997 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: Content Description #"November 1997, volume 130, number 617 (first of 4 numbers)."#On t.p. "P" is blackboard bold.#Includes bibliographical references.

Download or read book Reductive Subgroups of Exceptional Algebraic Groups written by Martin W. Liebeck and published by American Mathematical Soc.. This book was released on 1996 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theory of simple algebraic groups is important in many areas of mathematics. The authors of this book investigate the subgroups of certain types of simple algebraic groups and obtain a complete description of all those subgroups which are themselves simple. This description is particularly useful in understanding centralizers of subgroups and restrictions of representations.

Download or read book Lebesgue Theory in the Bidual of C X written by Samuel Kaplan and published by American Mathematical Soc.. This book was released on 1996 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present work is based upon our monograph "The Bidual of [italic capital]C([italic capital]X)" ([italic capital]X being compact). We generalize to the bidual the theory of Lebesgue integration, with respect to Radon measures on [italic capital]X, of bounded functions. The bidual of [italic capital]C([italic capital]X) contains this space of bounded functions, but is much more 'spacious', so the body of results can be expected to be richer. Finally, we show that by projection onto the space of bounded functions, the standard theory is obtained.

Download or read book Tilting in Abelian Categories and Quasitilted Algebras written by Dieter Happel and published by American Mathematical Soc.. This book was released on 1996 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: We generalize tilting with respect to a tilting module of projective dimension at most one for an Artin algebra to tilting with respect to a torsion pair in an Abelian category. Our construction is motivated by the connection between tilting and derived categories. We develop a general theory for such tilting, and are led to a generalization of tilting algebras which we call quasitilted algebras. This class also contains the canonical algebras, and we show that the quasitilted algebras are characterized by having global dimension at most two and each indecomposable module having projective dimension at most one or injective dimension at most one. We also give other characterizations of quasitilted algebras, and give methods for constructing such algebras.

Download or read book The Finite Irreducible Linear 2 Groups of Degree 4 written by Dane Laurence Flannery and published by American Mathematical Soc.. This book was released on 1997 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: This memoir contains a complete classification of the finite irreducible 2-subgroups of GL(4, C). Specifically, the author provides a parametrized list of representatives for the conjugacy classes of such groups, where each representative is defined by generating a set of monomial matrices. The problem is treated by a variety of techniques, including: elementary character theory; a method for describing Hasse diagrams of submodule lattices; and calculation of 2-cohomology by means of the Lyndon-Hochschild-Serre spectral sequence. Related questions concerning isomorphism between the listed groups and Schur indices of their defining characters are also considered

Download or read book Operators of Class C 0 with Spectra in Multiply Connected Regions written by Adele Zucchi and published by American Mathematical Soc.. This book was released on 1997 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the present paper the author studies the analogue of the class [italic capital]C0 within a class of operators having a functional calculus based on the algebra of bounded holomorphic functions in a finitely connected domain with an analytic boundary. The latter class consists of the operators having the closure of the domain as a spectral set and having no normal direct summands with spectra contained in the boundary of the domain. (If the domain is the disk the preceding class reduces to the class of completely nonunitary contractions.) The basic properties known for the case of the disk, including the model theory, are established. The extension, even the mere construction of the functional calculus, is not routine, in part because it is unknown whether the analogue of Sz.-Nagy's dilation theorem is true in the author's multiply connected setting.

Download or read book Lie Groups and Subsemigroups with Surjective Exponential Function written by Karl Heinrich Hofmann and published by American Mathematical Soc.. This book was released on 1997 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the structure theory of real Lie groups, there is still information lacking about the exponential function. Most notably, there are no general necessary and sufficient conditions for the exponential function to be surjective. It is surprising that for subsemigroups of Lie groups, the question of the surjectivity of the exponential function can be answered. Under nature reductions setting aside the "group part" of the problem, subsemigroups of Lie groups with surjective exponential function are completely classified and explicitly constructed in this memoir. There are fewer than one would think and the proofs are harder than one would expect, requiring some innovative twists. The main protagonists on the scene are SL(2, R) and its universal covering group, almost abelian solvable Lie groups (ie. vector groups extended by homotheties), and compact Lie groups. This text will also be of interest to those working in algebra and algebraic geometry.

Download or read book Symmetry Breaking for Compact Lie Groups written by Mike Field and published by American Mathematical Soc.. This book was released on 1996 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work comprises a general study of symmetry breaking for compact Lie groups in the context of equivariant bifurcation theory. We begin by extending the theory developed by Field and Richardson for absolutely irreducible representations of finite groups to general irreducible representations of compact Lie groups, while allowing for branches of relative equilibria and phenomena such as the Hopf bifurcation. We also present a general theory of determinacy for irreducible Lie group actions. We show that branching patterns for generic equivariant bifurcation problems defined on irreducible representations persist under perturbations by sufficiently high order non-equivariant terms.