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In this paper we give an alternative construction using Monk like algebras that are binary generated to show that the class of strongly representable atom structures is not elementary. The atom structures of such algebras are cylindric…

Logic · Mathematics 2013-07-17 Tarek Sayed Ahmed , Mohammed Khaled

We strengthen a result of Bagaria and Magidor~\cite{MR3152715} about the relationship between large cardinals and torsion classes of abelian groups, and prove that (1) the \emph{Maximum Deconstructibility} principle introduced in…

Logic · Mathematics 2024-09-27 Sean Cox , Alejandro Poveda , Jan Trlifaj

Michalski gave a short and elegant proof of a theorem of A. Kumar which states that for each set A in R, there exists a subset B of A which is full in A and such that no distance between points in B is a rational number. He also proved a…

Functional Analysis · Mathematics 2022-08-16 Sanjib Basu , Abhit Chandra Pramanik

In this paper we introduce the notion of existentially closed Leibniz algebras. Then we use HNN-extensions of Leibniz algebras in order to prove an embedding theorem.

Rings and Algebras · Mathematics 2021-08-17 Chia Zargeh

I prove preservation theorems for countable support iteration of proper forcing concerning certain classes of capacities and submeasures. New examples of forcing notions and connections with measure theory are included.

Logic · Mathematics 2007-05-23 Jindrich Zapletal

In this article, a concept of implicit methods for scalar conservation laws in one or more spatial dimensions allowing also for source terms of various types is presented. This material is a significant extension of previous work of the…

Analysis of PDEs · Mathematics 2016-09-29 Michael Breuß , Andreas Kleefeld

We prove existence of minimizers for the sharp Poincar\'e-Sobolev constant in general Steiner symmetric sets, in the subcritical and superhomogeneous regime. The sets considered are not necessarily bounded, thus the relevant embeddings may…

Analysis of PDEs · Mathematics 2025-05-19 Lorenzo Brasco , Luca Briani , Francesca Prinari

We extend Bourke and Garner's idempotent adjunction between monads and pretheories to the framework of $\infty$-categories and we use this to prove many classical results about monads in the $\infty$-categorical framework. Amongst other…

Category Theory · Mathematics 2021-06-17 Simon Henry , Nicholas J. Meadows

We study atom canonicity for several varieties of cylindric like algebras that contain properly the variety of representable algebras. The algebras in such varieties have relativized representations, and we thereby obtain many omitting…

Logic · Mathematics 2013-08-29 Tarek Sayed Ahmed

We show analogues of the classical Krein-Milman theorem for several ordered algebraic structures, especially in a semilattice (non-linear) framework. In that case, subsemilattices are seen as convex subsets, and for our proofs we use…

Functional Analysis · Mathematics 2014-05-30 Paul Poncet

We develop a number of basic concepts in the theory of categories internal to an $\infty$-topos. We discuss adjunctions, limits and colimits as well as Kan extensions for internal categories, and we use these results to prove the universal…

Category Theory · Mathematics 2024-02-14 Louis Martini , Sebastian Wolf

The categoricity spectrum of a class of structures is the collection of cardinals in which the class has a single model up to isomorphism. Assuming that cardinal exponentiation is injective (a weakening of the generalized continuum…

Logic · Mathematics 2019-10-03 Sebastien Vasey

A brief introduction to the theory of ordered sets and lattice theory is given. To illustrate proof techniques in the theory of ordered sets, a generalization of a conjecture of Daykin and Daykin, concerning the structure of posets that can…

Combinatorics · Mathematics 2009-09-25 Jonathan David Farley

We investigate categoricity of abstract elementary classes without any remnants of compactness (like non-definability of well ordering, existence of E.M. models or existence of large cardinals). We prove (assuming a weak version of GCH…

Logic · Mathematics 2016-09-07 Saharon Shelah

We provide a construction of the fixed points of functors which may not be inital algebras or final coalgebras. For an endofunctor F, this fixed point construction may be expressed as a pair of adjoint functors between F-coalgebras and…

Category Theory · Mathematics 2023-03-06 Ezra Schoen , Jade Master , Clemens Kupke

In this paper, we develop a new index theory for manifolds with polyhedral boundary. As an application, we prove Gromov's dihedral extremality conjecture regarding comparisons of scalar curvatures, mean curvatures and dihedral angles…

Differential Geometry · Mathematics 2023-03-09 Jinmin Wang , Zhizhang Xie , Guoliang Yu

We prove for a large family of rings R that their lambda-pure global dimension is greater than one for each infinite regular cardinal lambda. This answers in negative a problem posed by Rosicky. The derived categories of such rings then do…

Category Theory · Mathematics 2019-02-20 Silvana Bazzoni , Jan Stovicek

A quasi-schemoid is a small category whose morphisms are colored with appropriate combinatorial data. In this note, Mitchell's embedding theorem for a tame schemoid is established. The result allows us to give a cofibrantly generated model…

Category Theory · Mathematics 2016-02-29 Katsuhiko Kuribayashi , Yasuhiro Momose

We prove that if there is an elementary embedding from the universe to itself, then there is a proper class of measurable successor cardinals.

Logic · Mathematics 2021-11-03 Gabriel Goldberg

A poset is representable if it can be embedded in a field of sets in such a way that existing finite meets and joins become intersections and unions respectively (we say finite meets and joins are preserved). More generally, for cardinals…

Logic · Mathematics 2016-08-31 Rob Egrot