English
Related papers

Related papers: Atomic toposes and countable categoricity

200 papers

We develop a representation theory of categories as a means to explore characteristic structures in algebra. Characteristic structures play a critical role in isomorphism testing of groups and algebras, and their construction and…

Group Theory · Mathematics 2025-11-20 Peter A. Brooksbank , Heiko Dietrich , Joshua Maglione , E. A. O'Brien , James B. Wilson

We show there exists a complete theory in a language of size continuum possessing a unique atomic model which is not constructible. We also show it is consistent with $ZFC + \aleph_1 < 2^{\aleph_0}$ that there is a complete theory in a…

Logic · Mathematics 2016-07-27 Douglas Ulrich

The basic notion of how topoi can be utilized in physics is presented here. Topos and category theory serve as valuable tools which extend our ordinary set-theoretical conceptions, can further the study of quantum logic and give rise to new…

Mathematical Physics · Physics 2008-03-18 Marios Tsatsos

In proper homotopy theory, the original concept of point used in the classical homotopy theory of topological spaces is generalized in order to obtain homotopy groups that study the infinite of the spaces. This idea: "Using any arbitrary…

Algebraic Topology · Mathematics 2012-03-05 Francisco J. Díaz , José M. G. Calcines

We give a detailed and self-contained introduction to the theory of $\lambda $-toposes and prove the following: 1) A $\lambda $-separable $\lambda $-topos has enough $\lambda $-points. 2) The classifying $\lambda $-topos of a $\kappa $-site…

Category Theory · Mathematics 2025-05-16 Christian Espíndola , Kristóf Kanalas

The structures $\langle M,\subseteq^M\rangle$ arising as the inclusion relation of a countable model of sufficient set theory $\langle M,\in^M\rangle$, whether well-founded or not, are all isomorphic. These structures $\langle…

Logic · Mathematics 2017-04-17 Joel David Hamkins , Makoto Kikuchi

It is shown that every separable abelian topological group is isomorphic with a topological subgroup of a monothetic group (that is, a topological group with a single topological generator). In particular, every separable metrizable abelian…

General Topology · Mathematics 2007-09-03 Sidney A. Morris , Vladimir Pestov

We explore the possibility of replacing point set topology by higher category theory and topos theory as the foundation for quantum general relativity. We discuss the BC model and problems of its interpretation, and connect with the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Louis Crane

We prove that every many-sorted $\omega$-categorical theory is completely interpretable in a one-sorted $\omega$-categorical theory. As an application, we give a short proof of the existence of non $G$--compact $\omega$-categorical…

Logic · Mathematics 2011-03-21 Enrique Casanovas , Rodrigo Peláez , Martin Ziegler

We discuss some ways in which topos theory (a branch of category theory) can be applied to interpretative problems in quantum theory and quantum gravity. In Section 1, we introduce these problems. In Section 2, we introduce topos theory,…

General Relativity and Quantum Cosmology · Physics 2011-04-20 C. J. Isham , J. Butterfield

We present an abstract unifying framework for interpreting Stone-type dualities; several known dualities are seen to be instances of just one topos-theoretic phenomenon, and new dualities are introduced. In fact, infinitely many new…

Category Theory · Mathematics 2011-04-06 Olivia Caramello

We discuss here geometric structures of condensed matters by means of a fundamental topological method. Any geometric pattern can be universally represented by a decomposition space of a topological space consisting of the infinite product…

Mathematical Physics · Physics 2019-09-04 Shousuke Ohmori , Yoshihiro Yamazaki , Tomoyuki Yamamoto , Akihiko Kitada

We introduce and investigate the category $\mathsf{AtoMon}$ of atomic monoids and atom-preserving monoid homomorphisms, which is a (non-full) subcategory of the usual category of monoids. In particular, we compute all limits and colimits,…

Rings and Algebras · Mathematics 2025-02-11 Federico Campanini , Laura Cossu , Salvatore Tringali

We construct classifying spaces for discrete and compact Lie groups, with the property that they are topological groups and complete metric spaces in a natural way. We sketch a program in view of extending these constructions.

Algebraic Topology · Mathematics 2017-02-08 Ivan Marin

We give a quick survey of the various fixed point theorems in computability theory, partial combinatory algebra, and the theory of numberings, as well as generalizations based on those. We also point out several open problems connected to…

Logic · Mathematics 2024-02-06 Sebastiaan A. Terwijn

The notion of an existentially closed model is generalised to a property of geometric morphisms between toposes. We show that important properties of existentially closed models extend to existentially closed geometric morphisms, such as…

Category Theory · Mathematics 2024-06-06 Mark Kamsma , Joshua Wrigley

This thesis provides an introduction to the various category theory ideas employed in topological quantum field theory. These theories are viewed as symmetric monoidal functors from topological cobordism categories into the category of…

Quantum Algebra · Mathematics 2007-05-23 Bruce H. Bartlett

We define E-theory for separable C*-algebras over second countable topological spaces and establish its basic properties. This includes an approximation theorem that relates the E-theory over a general space to the E-theories over finite…

K-Theory and Homology · Mathematics 2015-10-23 Marius Dadarlat , Ralf Meyer

The concept of typed topological space is introduced, for which open sets in a topology on a finite set will be assigned types (from lattice). The neighborhood system of a point, the closure and the connectedness can be defined according to…

General Topology · Mathematics 2018-04-13 Wanjun Hu

A general theory of topological classification of defects is introduced. We illustrate the application of tools from algebraic topology, including homotopy and cohomology groups, to classify defects including several explicit calculations…

Mathematical Physics · Physics 2021-06-15 Nivedita , Anurag Gupta