Classes of Polish Spaces Under Effective Borel Isomorphism

Classes of Polish Spaces Under Effective Borel Isomorphism PDF Author: Vassilios Gregoriades
Publisher: American Mathematical Soc.
ISBN: 1470415631
Category : Mathematics
Languages : en
Pages : 102

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Book Description
The author studies the equivalence classes under Δ11 isomorphism, otherwise effective Borel isomorphism, between complete separable metric spaces which admit a recursive presentation and he shows the existence of strictly increasing and strictly decreasing sequences as well as of infinite antichains under the natural notion of Δ11-reduction, as opposed to the non-effective case, where only two such classes exist, the one of the Baire space and the one of the naturals.

Classes of Polish Spaces Under Effective Borel Isomorphism

Classes of Polish Spaces Under Effective Borel Isomorphism PDF Author: Vassilios Gregoriades
Publisher: American Mathematical Soc.
ISBN: 1470415631
Category : Mathematics
Languages : en
Pages : 102

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Book Description
The author studies the equivalence classes under Δ11 isomorphism, otherwise effective Borel isomorphism, between complete separable metric spaces which admit a recursive presentation and he shows the existence of strictly increasing and strictly decreasing sequences as well as of infinite antichains under the natural notion of Δ11-reduction, as opposed to the non-effective case, where only two such classes exist, the one of the Baire space and the one of the naturals.

Classes of Polish Spaces Under Effective Borel Isomorphism

Classes of Polish Spaces Under Effective Borel Isomorphism PDF Author: Vassilios Gregoriades
Publisher:
ISBN: 9781470428228
Category : Isomorphisms (Mathematics)
Languages : en
Pages : 87

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Book Description


Descriptional Complexity of Formal Systems

Descriptional Complexity of Formal Systems PDF Author: Michal Hospodár
Publisher: Springer
ISBN: 3030232476
Category : Computers
Languages : en
Pages : 309

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Book Description
This book constitutes the proceedings of the 21st International Conference on Descriptional Complexity of Format Systems, DCFS 2019, held in Košice, Slovakia, in July 2019. The 18 full papers presented in this volume were carefully reviewed and selected from 25 submissions. The book also contains 4 invited talks. They deal with all aspects of descriptional complexity and costs of description of objects in various computational models, such as Turing machines, pushdown automata, finite automata, grammars, and others.

Handbook of Computability and Complexity in Analysis

Handbook of Computability and Complexity in Analysis PDF Author: Vasco Brattka
Publisher: Springer Nature
ISBN: 3030592340
Category : Computers
Languages : en
Pages : 427

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Book Description
Computable analysis is the modern theory of computability and complexity in analysis that arose out of Turing's seminal work in the 1930s. This was motivated by questions such as: which real numbers and real number functions are computable, and which mathematical tasks in analysis can be solved by algorithmic means? Nowadays this theory has many different facets that embrace topics from computability theory, algorithmic randomness, computational complexity, dynamical systems, fractals, and analog computers, up to logic, descriptive set theory, constructivism, and reverse mathematics. In recent decades computable analysis has invaded many branches of analysis, and researchers have studied computability and complexity questions arising from real and complex analysis, functional analysis, and the theory of differential equations, up to (geometric) measure theory and topology. This handbook represents the first coherent cross-section through most active research topics on the more theoretical side of the field. It contains 11 chapters grouped into parts on computability in analysis; complexity, dynamics, and randomness; and constructivity, logic, and descriptive complexity. All chapters are written by leading experts working at the cutting edge of the respective topic. Researchers and graduate students in the areas of theoretical computer science and mathematical logic will find systematic introductions into many branches of computable analysis, and a wealth of information and references that will help them to navigate the modern research literature in this field.

Evolving Computability

Evolving Computability PDF Author: Arnold Beckmann
Publisher: Springer
ISBN: 3319200283
Category : Computers
Languages : en
Pages : 375

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Book Description
This book constitutes the refereed proceedings of the 11th Conference on Computability in Europe, CiE 2015, held in Bucharest, Romania, in June/July 2015. The 26 revised papers presented were carefully reviewed and selected from 64 submissions and included together with 10 invited papers in this proceedings. The conference CiE 2015 has six special sessions: two sessions, Representing Streams and Reverse Mathematics, were introduced for the first time in the conference series. In addition to this, new developments in areas frequently covered in the CiE conference series were addressed in the further special sessions on Automata, Logic and Infinite Games; Bio-inspired Computation; Classical Computability Theory; as well as History and Philosophy of Computing.

Hyperbolically Embedded Subgroups and Rotating Families in Groups Acting on Hyperbolic Spaces

Hyperbolically Embedded Subgroups and Rotating Families in Groups Acting on Hyperbolic Spaces PDF Author: F. Dahmani
Publisher: American Mathematical Soc.
ISBN: 1470421941
Category : Mathematics
Languages : en
Pages : 164

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Book Description
he authors introduce and study the notions of hyperbolically embedded and very rotating families of subgroups. The former notion can be thought of as a generalization of the peripheral structure of a relatively hyperbolic group, while the latter one provides a natural framework for developing a geometric version of small cancellation theory. Examples of such families naturally occur in groups acting on hyperbolic spaces including hyperbolic and relatively hyperbolic groups, mapping class groups, , and the Cremona group. Other examples can be found among groups acting geometrically on spaces, fundamental groups of graphs of groups, etc. The authors obtain a number of general results about rotating families and hyperbolically embedded subgroups; although their technique applies to a wide class of groups, it is capable of producing new results even for well-studied particular classes. For instance, the authors solve two open problems about mapping class groups, and obtain some results which are new even for relatively hyperbolic groups.

$L^p$-Square Function Estimates on Spaces of Homogeneous Type and on Uniformly Rectifiable Sets

$L^p$-Square Function Estimates on Spaces of Homogeneous Type and on Uniformly Rectifiable Sets PDF Author: Steve Hofmann
Publisher: American Mathematical Soc.
ISBN: 1470422603
Category : Mathematics
Languages : en
Pages : 120

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Book Description
The authors establish square function estimates for integral operators on uniformly rectifiable sets by proving a local theorem and applying it to show that such estimates are stable under the so-called big pieces functor. More generally, they consider integral operators associated with Ahlfors-David regular sets of arbitrary codimension in ambient quasi-metric spaces. The local theorem is then used to establish an inductive scheme in which square function estimates on so-called big pieces of an Ahlfors-David regular set are proved to be sufficient for square function estimates to hold on the entire set. Extrapolation results for and Hardy space versions of these estimates are also established. Moreover, the authors prove square function estimates for integral operators associated with variable coefficient kernels, including the Schwartz kernels of pseudodifferential operators acting between vector bundles on subdomains with uniformly rectifiable boundaries on manifolds.

Locally Analytic Vectors in Representations of Locally $p$-adic Analytic Groups

Locally Analytic Vectors in Representations of Locally $p$-adic Analytic Groups PDF Author: Matthew J. Emerton
Publisher: American Mathematical Soc.
ISBN: 0821875620
Category : Mathematics
Languages : en
Pages : 168

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Book Description
The goal of this memoir is to provide the foundations for the locally analytic representation theory that is required in three of the author's other papers on this topic. In the course of writing those papers the author found it useful to adopt a particular point of view on locally analytic representation theory: namely, regarding a locally analytic representation as being the inductive limit of its subspaces of analytic vectors (of various “radii of analyticity”). The author uses the analysis of these subspaces as one of the basic tools in his study of such representations. Thus in this memoir he presents a development of locally analytic representation theory built around this point of view. The author has made a deliberate effort to keep the exposition reasonably self-contained and hopes that this will be of some benefit to the reader.

The Local Structure Theorem for Finite Groups With a Large $p$-Subgroup

The Local Structure Theorem for Finite Groups With a Large $p$-Subgroup PDF Author: U. Meierfrankenfeld
Publisher: American Mathematical Soc.
ISBN: 1470418770
Category : Mathematics
Languages : en
Pages : 356

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Book Description
Let p be a prime, G a finite Kp-group S a Sylow p-subgroup of G and Q a large subgroup of G in S (i.e., CG(Q)≤Q and NG(U)≤NG(Q) for 1≠U≤CG(Q)). Let L be any subgroup of G with S≤L, Op(L)≠1 and Q⋬L. In this paper the authors determine the action of L on the largest elementary abelian normal p-reduced p-subgroup YL of L.

Proof of the 1-Factorization and Hamilton Decomposition Conjectures

Proof of the 1-Factorization and Hamilton Decomposition Conjectures PDF Author: Béla Csaba
Publisher: American Mathematical Soc.
ISBN: 1470420252
Category : Mathematics
Languages : en
Pages : 176

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Book Description
In this paper the authors prove the following results (via a unified approach) for all sufficiently large n: (i) [1-factorization conjecture] Suppose that n is even and D≥2⌈n/4⌉−1. Then every D-regular graph G on n vertices has a decomposition into perfect matchings. Equivalently, χ′(G)=D. (ii) [Hamilton decomposition conjecture] Suppose that D≥⌊n/2⌋. Then every D-regular graph G on n vertices has a decomposition into Hamilton cycles and at most one perfect matching. (iii) [Optimal packings of Hamilton cycles] Suppose that G is a graph on n vertices with minimum degree δ≥n/2. Then G contains at least regeven(n,δ)/2≥(n−2)/8 edge-disjoint Hamilton cycles. Here regeven(n,δ) denotes the degree of the largest even-regular spanning subgraph one can guarantee in a graph on n vertices with minimum degree δ. (i) was first explicitly stated by Chetwynd and Hilton. (ii) and the special case δ=⌈n/2⌉ of (iii) answer questions of Nash-Williams from 1970. All of the above bounds are best possible.