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We study a strengthening of the notion of a universally meager set and its dual counterpart that strengthens the notion of a universally null set. We say that a subset $A$ of a perfect Polish space $X$ is countably perfectly meager…

Logic · Mathematics 2023-04-18 Tomasz Weiss , Piotr Zakrzewski

We examine the existence of universal elements in classes of infinite abelian groups. The main method is using group invariants which are defined relative to club guessing sequences. We prove, for example: Theorem: For $n\ge 2$, there is a…

Logic · Mathematics 2016-09-06 Menachem Kojman , Saharon Shelah

We prove that, for every integer $n \ge 2$, a finite or infinite countable group $G$ can be embedded into a 2-generated group $H$ in such a way that the solvability of quadratic equations of length at most $n$ is preserved, i.e., every…

Group Theory · Mathematics 2016-07-25 Desmond F. Cummins , Sergei V. Ivanov

We propound the thesis that there is a limitation to the number of possible structures which are axiomatically endowed with identities involving operations. In the case of algebras with a binary operation satisfying a formally reducible (to…

Rings and Algebras · Mathematics 2007-05-23 Constantin M. Petridi , P. B. Krikelis

In the additive topological group $(\mathbb{R},+)$ of real numbers, we construct families of sets for which elements are not measurable in the Lebesgue sense. The constructed families have algebraic structures of being semigroups (i.e.,…

Functional Analysis · Mathematics 2024-08-13 Venuste Nyagahakwa , Gratien Haguma , Joseline Munyaneza

Let L be a countable language. We say that a countable infinite L-structure M admits an invariant measure when there is a probability measure on the space of L-structures with the same underlying set as M that is invariant under…

Logic · Mathematics 2016-06-29 Nathanael Ackerman , Cameron Freer , Rehana Patel

A result of Kaufmann shows that if $L_\alpha$ is countable, admissible and satisfies $\Pi_n\textsf{-Collection}$, then $\langle L_\alpha, \in \rangle$ has a proper $\Sigma_{n+1}$-elementary end extension. This paper investigates to what…

Logic · Mathematics 2022-01-14 Zachiri McKenzie

Learning word embeddings using distributional information is a task that has been studied by many researchers, and a lot of studies are reported in the literature. On the contrary, less studies were done for the case of multiple languages.…

Computation and Language · Computer Science 2020-04-15 Marco Berlot , Evan Kaplan

Binary multirelations form a model of alternating nondeterminism useful for analysing games, interactions of computing systems with their environments or abstract interpretations of probabilistic programs. We investigate this alternating…

Logic in Computer Science · Computer Science 2023-06-13 Hitoshi Furusawa , Walter Guttmann , Georg Struth

We find all finite Ockham algebras that admit only finitely many compatible relations (modulo a natural equivalence). Up to isomorphism and symmetry, these Ockham algebras form two countably infinite families: one family consists of the…

Rings and Algebras · Mathematics 2015-01-13 Brian A. Davey , Long T. Nguyen , Jane G. Pitkethly

An algebra is finitely related (or has finite degree) if its term functions are determined by some finite set of finitary relations. Nilpotent monoids built from words, via Rees quotients of free monoids, have been used to exhibit many…

Group Theory · Mathematics 2024-07-08 Daniel Glasson

The main aim of this paper is to determine the multiplicative lie algebra structures on the semi-direct product of an abelian group with a group under certain conditions.

Group Theory · Mathematics 2023-05-22 Deepak Pal , Amit Kumar , Sumit Kumar Upadhyay , Seema Kushwaha

A subset $A$ of a Boolean algebra $B$ is said to be $(n,m)$-reaped if there is a partition of unity $P \subset B$ of size $n$ such that the cardinality of $\{b \in P: b \wedge a \neq \emptyset\}$ is greater than or equal to $m$ for all…

Logic · Mathematics 2008-02-03 A. Dow , J Steprāns , W. S. Watson

A deductive system is structurally complete if its admissible inference rules are derivable. For several important systems, like modal logic S5, failure of structural completeness is caused only by the underivability of passive rules, i.e.…

Logic · Mathematics 2014-08-26 Wojciech Dzik , Michal M. Stronkowski

We prove non-commutative reciprocity laws on an algebraic surface defined over a perfect field. These reciprocity laws claim the splittings of some central extensions of globally constructed groups over some subgroups constructed by points…

Algebraic Geometry · Mathematics 2014-05-19 D. V. Osipov

We consider a specific class of tree structures that can represent basic structures in linguistics and computer science such as XML documents, parse trees, and treebanks, namely, finite node-labeled sibling-ordered trees. We present…

Logic in Computer Science · Computer Science 2015-07-01 Amélie Gheerbrant , Balder ten Cate

Maximally embedding dimension (MED) numerical semigroups are a wide and interesting family, with some remarkable algebraic and combinatorial properties. Associated to any numerical semigroup one can construct a MED closure, as it is well…

Combinatorics · Mathematics 2025-01-22 Jorge Jiménez Urroz , José M. Tornero

Let A be an algebra with a countable basis and let B be, say, a Frechet algebra that contains A as a dense subalgebra. This embedding induces a functor from the derived category of B-modules to the derived category of A-modules. In many…

Functional Analysis · Mathematics 2007-05-23 Ralf Meyer

For every countable structure $M$ we construct an $\aleph_0$-stable countable structure $N$ such that $Aut(M)$ and $Aut(N)$ are topologically isomorphic. This shows that it is impossible to detect any form of stability of a countable…

Logic · Mathematics 2018-11-20 Gianluca Paolini , Saharon Shelah

We combine computable structure theory and algorithmic learning theory to study learning of families of algebraic structures. Our main result is a model-theoretic characterization of the class $\mathbf{InfEx}_{\cong}$, consisting of the…

Logic · Mathematics 2021-03-19 Nikolay Bazhenov , Ekaterina Fokina , Luca San Mauro