Descriptive Set Theory and Definable Forcing

Descriptive Set Theory and Definable Forcing
Author: Jindřich Zapletal
Publisher: American Mathematical Soc.
Total Pages: 158
Release: 2004
Genre: Mathematics
ISBN: 0821834509

Focuses on the relationship between definable forcing and descriptive set theory; the forcing serves as a tool for proving independence of inequalities between cardinal invariants of the continuum.

Forcing For Mathematicians

Forcing For Mathematicians
Author: Nik Weaver
Publisher: World Scientific
Total Pages: 153
Release: 2014-01-24
Genre: Mathematics
ISBN: 9814566020

Ever since Paul Cohen's spectacular use of the forcing concept to prove the independence of the continuum hypothesis from the standard axioms of set theory, forcing has been seen by the general mathematical community as a subject of great intrinsic interest but one that is technically so forbidding that it is only accessible to specialists. In the past decade, a series of remarkable solutions to long-standing problems in C*-algebra using set-theoretic methods, many achieved by the author and his collaborators, have generated new interest in this subject. This is the first book aimed at explaining forcing to general mathematicians. It simultaneously makes the subject broadly accessible by explaining it in a clear, simple manner, and surveys advanced applications of set theory to mainstream topics.

Classical Descriptive Set Theory

Classical Descriptive Set Theory
Author: Alexander Kechris
Publisher: Springer Science & Business Media
Total Pages: 419
Release: 2012-12-06
Genre: Mathematics
ISBN: 1461241901

Descriptive set theory has been one of the main areas of research in set theory for almost a century. This text presents a largely balanced approach to the subject, which combines many elements of the different traditions. It includes a wide variety of examples, more than 400 exercises, and applications, in order to illustrate the general concepts and results of the theory.

Geometric Set Theory

Geometric Set Theory
Author: Paul B. Larson
Publisher: American Mathematical Soc.
Total Pages: 345
Release: 2020-07-16
Genre: Education
ISBN: 1470454629

This book introduces a new research direction in set theory: the study of models of set theory with respect to their extensional overlap or disagreement. In Part I, the method is applied to isolate new distinctions between Borel equivalence relations. Part II contains applications to independence results in Zermelo–Fraenkel set theory without Axiom of Choice. The method makes it possible to classify in great detail various paradoxical objects obtained using the Axiom of Choice; the classifying criterion is a ZF-provable implication between the existence of such objects. The book considers a broad spectrum of objects from analysis, algebra, and combinatorics: ultrafilters, Hamel bases, transcendence bases, colorings of Borel graphs, discontinuous homomorphisms between Polish groups, and many more. The topic is nearly inexhaustible in its variety, and many directions invite further investigation.

The Role of the Spectrum in the Cyclic Behavior of Composition Operators

The Role of the Spectrum in the Cyclic Behavior of Composition Operators
Author: Eva A. Gallardo-Gutieŕrez
Publisher: American Mathematical Soc.
Total Pages: 98
Release: 2004
Genre: Mathematics
ISBN: 0821834320

Introduction and preliminaries Linear fractional maps with an interior fixed point Non elliptic automorphisms The parabolic non automorphism Supercyclic linear fractional composition operators Endnotes Bibliography.

Quasi-Ordinary Power Series and Their Zeta Functions

Quasi-Ordinary Power Series and Their Zeta Functions
Author: Enrique Artal-Bartolo
Publisher: American Mathematical Soc.
Total Pages: 100
Release: 2005-10-05
Genre: Functions, Zeta
ISBN: 9780821865637

The main objective of this paper is to prove the monodromy conjecture for the local Igusa zeta function of a quasi-ordinary polynomial of arbitrary dimension defined over a number field. In order to do it, we compute the local Denef-Loeser motivic zeta function $Z_{\text{DL}}(h,T)$ of a quasi-ordinary power series $h$ of arbitrary dimension over an algebraically closed field of characteristic zero from its characteristic exponents without using embedded resolution of singularities. This allows us to effectively represent $Z_{\text{DL}}(h,T)=P(T)/Q(T)$ such that almost all the candidate poles given by $Q(T)$ are poles. Anyway, these candidate poles give eigenvalues of the monodromy action on the complex $R\psi_h$ of nearby cycles on $h^{-1}(0).$ In particular we prove in this case the monodromy conjecture made by Denef-Loeser for the local motivic zeta function and the local topological zeta function. As a consequence, if $h$ is a quasi-ordinary polynomial defined over a number field we prove the Igusa monodromy conjecture for its local Igusa zeta function.

Uniformizing Dessins and BelyiMaps via Circle Packing

Uniformizing Dessins and BelyiMaps via Circle Packing
Author: Philip L. Bowers
Publisher: American Mathematical Soc.
Total Pages: 118
Release: 2004
Genre: Mathematics
ISBN: 0821835238

Introduction Dessins d'enfants Discrete Dessins via circle packing Uniformizing Dessins A menagerie of Dessins d'enfants Computational issues Additional constructions Non-equilateral triangulations The discrete option Appendix: Implementation Bibliography.

A Sharp Threshold for Random Graphs with a Monochromatic Triangle in Every Edge Coloring

A Sharp Threshold for Random Graphs with a Monochromatic Triangle in Every Edge Coloring
Author: Ehud Friedgut
Publisher: American Mathematical Soc.
Total Pages: 80
Release: 2006
Genre: Mathematics
ISBN: 0821838253

Let $\cal{R}$ be the set of all finite graphs $G$ with the Ramsey property that every coloring of the edges of $G$ by two colors yields a monochromatic triangle. In this paper the authors establish a sharp threshold for random graphs with this property. Let $G(n, p)$ be the random graph on $n$ vertices with edge probability $p$. The authors prove that there exists a function $\widehat c=\widehat c(n)=\Theta(1)$ such that for any $\varepsilon > 0$, as $n$ tends to infinity, $Pr\left[G(n, (1-\varepsilon)\widehat c/\sqrt{n}) \in \cal{R} \right] \rightarrow 0$ and $Pr \left[ G(n, (1]\varepsilon)\widehat c/\sqrt{n}) \in \cal{R}\ \right] \rightarrow 1.$. A crucial tool that is used in the proof and is of independent interest is a generalization of Szemeredi's Regularity Lemma to a certain hypergraph setti

Exceptional Vector Bundles, Tilting Sheaves and Tilting Complexes for Weighted Projective Lines

Exceptional Vector Bundles, Tilting Sheaves and Tilting Complexes for Weighted Projective Lines
Author: Hagen Meltzer
Publisher: American Mathematical Soc.
Total Pages: 154
Release: 2004
Genre: Mathematics
ISBN: 082183519X

Deals with weighted projective lines, a class of non-commutative curves modelled by Geigle and Lenzing on a graded commutative sheaf theory. They play an important role in representation theory of finite-dimensional algebras; the complexity of the classification of coherent sheaves largely depends on the genus of these curves.

Kahler Spaces, Nilpotent Orbits, and Singular Reduction

Kahler Spaces, Nilpotent Orbits, and Singular Reduction
Author: Johannes Huebschmann
Publisher: American Mathematical Soc.
Total Pages: 110
Release: 2004
Genre: Mathematics
ISBN: 0821835726

For a stratified symplectic space, a suitable concept of stratified Kahler polarization encapsulates Kahler polarizations on the strata and the behaviour of the polarizations across the strata and leads to the notion of stratified Kahler space which establishes an intimate relationship between nilpotent orbits, singular reduction, invariant theory, reductive dual pairs, Jordan triple systems, symmetric domains, and pre-homogeneous spaces: The closure of a holomorphic nilpotent orbit or, equivalently, the closure of the stratum of the associated pre-homogeneous space of parabolic type carries a (positive) normal Kahler structure. In the world of singular Poisson geometry, the closures of principal holomorphic nilpotent orbits, positive definite hermitian JTS's, and certain pre-homogeneous spaces appear as different incarnations of the same structure. The closure of the principal holomorphic nilpotent orbit arises from a semisimple holomorphic orbit by contraction. Symplectic reduction carries a positive Kahler manifold to a positive normal Kahler space in such a way that the sheaf of germs of polarized functions coincides with the ordinary sheaf of germs of holomorphic functions. Symplectic reduction establishes a close relationship between singular reduced spaces and nilpotent orbits of the dual groups. Projectivization of holomorphic nilpotent orbits yields exotic (positive) stratified Kahler structures on complex projective spaces and on certain complex projective varieties including complex projective quadrics. The space of (in general twisted) representations of the fundamental group of a closed surface in a compact Lie group or, equivalently, a moduli space of central Yang-Mills connections on a principal bundle over a surface, inherits a (positive) normal (stratified) Kahler structure. Physical examples are provided by certain reduced spaces arising from angular momentum zero.