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In the paper, we consider the class of so-called endo-commutative algebras. From the identity imposed to specify this class, one can easily see that the product in this class preserves the square of elements. We give a complete…

Rings and Algebras · Mathematics 2024-07-09 D. Asrorov , U. Bekbaev , I. Rakhimov

We compute the monoid $V(L_K(E))$ of isomorphism classes of finitely generated projective modules over certain graph algebras $L_K(E)$, and we show that this monoid satisfies the refinement property and separative cancellation. We also show…

Rings and Algebras · Mathematics 2007-05-23 P. Ara , M. A. Moreno , E. Pardo

We prove that every endomorphism of the mapping class group of an orientable surface onto a subgroup of finite index is in fact an automorphism.

Geometric Topology · Mathematics 2007-05-23 Mustafa Korkmaz

We study the complexity of the Graph Isomorphism problem on graph classes that are characterized by a finite number of forbidden induced subgraphs, focusing mostly on the case of two forbidden subgraphs. We show hardness results and develop…

Data Structures and Algorithms · Computer Science 2015-03-20 Stefan Kratsch , Pascal Schweitzer

We present results and examples which show that the consideration of a certain tubular mutation is advantageous in the study of noncommutative curves which parametrize the simple regular representations of a tame bimodule. We classify all…

Representation Theory · Mathematics 2008-06-16 Dirk Kussin

We consider large uniform labeled random graphs in different classes with prescribed decorations in their modular decomposition. Our main result is the estimation of the number of copies of every graph as an induced subgraph. As a…

Combinatorics · Mathematics 2023-10-25 Théo Lenoir

We study the uniqueness of optimal solutions to extremal graph theory problems. Lovasz conjectured that every finite feasible set of subgraph density constraints can be extended further by a finite set of density constraints so that the…

Combinatorics · Mathematics 2020-08-26 Andrzej Grzesik , Daniel Král' , László Miklós Lovász

Let $\Lambda$ be a finite dimensional algebra over an algebraically closed field. Criteria are given which characterize existence of a fine or coarse moduli space classifying, up to isomorphism, the representations of $\Lambda$ with fixed…

Representation Theory · Mathematics 2014-07-11 Birge Huisgen-Zimmermann

Let $A\subset B$ be an extension of commutative reduced rings and $M\subset N$ an extension of positive commutative cancellative torsion-free monoids. We prove that $A$ is subintegrally closed in $B$ and $M$ is subintegrally closed in $N$…

Commutative Algebra · Mathematics 2015-05-21 Husney Parvez Sarwar

A graph $U$ is universal for a graph class $\mathcal{C}\ni U$, if every $G\in \mathcal{C}$ is a minor of $U$. We prove the existence or absence of universal graphs in several natural graph classes, including graphs component-wise embeddable…

Combinatorics · Mathematics 2022-12-13 Agelos Georgakopoulos

This work is the extension of the results by the author in [7] and [6] for low-genus surfaces. Let $S$ be an orientable, connected surface of finite topological type, with genus $g \leq 2$, empty boundary, and complexity at least $2$; as a…

Geometric Topology · Mathematics 2026-05-27 Jesús Hernández Hernández

The zero-divisor graph of a finite commutative ring with unity is the graph whose vertex set is the set of zero-divisors in the ring, with $a$ and $b$ adjacent if $ab=0$. We show that the class of zero-divisor graphs is universal, in the…

Rings and Algebras · Mathematics 2022-07-26 G. Arunkumar , Peter J. Cameron , T. Kavaskar , T. Tamizh Chelvam

In this short note, we give a new sufficient condition for a linear map from a product of copies of a field to endomorphisms of a finite dimensional vector space over the same field to be an algebra homomorphism. We expect that this result…

Rings and Algebras · Mathematics 2015-07-31 Rajesh S. Kulkarni , Yusuf Mustopa , Ian Shipman

We prove that assuming suitable cardinal arithmetic, if B is a Boolean algebra every homomorphic image of which is isomorphic to a factor, then B has locally small density. We also prove that for an (infinite) Boolean algebra B, the number…

Logic · Mathematics 2008-02-03 Saharon Shelah

We investigate the question how `small' a graph can be, if it contains all members of a given class of locally finite graphs as subgraphs or induced subgraphs. More precisely, we give necessary and sufficient conditions for the existence of…

Combinatorics · Mathematics 2022-05-26 Florian Lehner

Every small monoidal category with universal finite joins of central idempotents is monoidally equivalent to the category of global sections of a sheaf of local monoidal categories on a topological space. Every small stiff monoidal category…

Category Theory · Mathematics 2023-02-09 Rui Soares Barbosa , Chris Heunen

In this note we prove that any affine algebraic monoid can be obtained as the endomorphisms' monoid of a finite-dimensional (nonassociative) algebra.

Algebraic Geometry · Mathematics 2025-03-06 Alexander Perepechko

In 2001 Enoch's celebrated flat cover conjecture was finally proven and the proofs (two different proofs were presented in the same paper [4]) have since generated a great deal of interest among researchers. In particular the results have…

Group Theory · Mathematics 2012-06-15 Alex Bailey , James Renshaw

We prove a flatness result for entire nonlocal minimal graphs having some partial derivatives bounded from either above or below. This result generalizes fractional versions of classical theorems due to Bernstein and Moser. Our arguments…

Analysis of PDEs · Mathematics 2018-12-06 Matteo Cozzi , Alberto Farina , Luca Lombardini

Given a row-finite higher-rank $k$-graph $\Lambda$, we define a commutative monoid $T_\Lambda$ which is a higher-rank analogue of the talented monoid of a directed graph. The talented monoid $T_\Lambda$ is canonically a…

Rings and Algebras · Mathematics 2024-11-13 Roozbeh Hazrat , Promit Mukherjee , David Pask , Sujit Kumar Sardar