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We investigate the complexity of isomorphism relations for classes of finitely generated and n-generated computably enumerable (c.e.) algebras, presented via c.e. presentations -- that is, as quotients of term algebras over decidable sets…

Logic · Mathematics 2026-01-21 Meng-Che "Turbo" Ho , Martin Ritter , Luca San Mauro

A classical problem in algebraic deformation theory is whether an infinitesimal deformation can be extended to a formal deformation. The answer to this question is usually given in terms of Massey powers. If all Massey powers of the…

Representation Theory · Mathematics 2007-05-23 Alice Fialowski , Michael Penkava

Given a simple vertex algebra A and a reductive group G of automorphisms of A, the invariant subalgebra A^G is strongly finitely generated in most examples where its structure is known. This phenomenon is subtle, and is generally not true…

Representation Theory · Mathematics 2020-08-10 Andrew R. Linshaw

Suppose a finite group acts on a scheme X and a finite-dimensional Lie algebra g. The corresponding equivariant map algebra is the Lie algebra M of equivariant regular maps from X to g. We classify the irreducible finite-dimensional…

Representation Theory · Mathematics 2012-04-11 Erhard Neher , Alistair Savage , Prasad Senesi

Given an algebra A, presented by generators and relations, i.e. as a quotient of a tensor algebra by an ideal, we construct a free algebra resolution of A, i.e. a differential graded algebra which is quasi-isomorphic to A and which is…

Rings and Algebras · Mathematics 2012-10-22 Joe Chuang , Alastair King

Given a graded module over a commutative ring, we define a dg-Lie algebra whose Maurer-Cartan elements are the strictly unital A-infinity algebra structures on that module. We use this to generalize Positselski's result that a curvature…

K-Theory and Homology · Mathematics 2018-01-23 Jesse Burke

We study (not necessarily connected) Z-graded A-infinity-algebras and their A-infinity-modules. Using the cobar and the bar construction and Quillen's homotopical algebra, we describe the localisation of the category of A-infinity-algebras…

Category Theory · Mathematics 2007-05-23 Kenji Lefèvre-Hasegawa

Let $E\supseteq F$ be a field extension and $M$ a graded Lie algebra of maximal class over $E$. We investigate the $F$-subalgebras $L$ of $M$, generated by elements of degree $1$. We provide conditions for $L$ being either ideally…

Rings and Algebras · Mathematics 2023-11-14 Marina Avitabile , Norberto Gavioli , Valerio Monti

Let $P$ be a unital subsemigroup of a group $G$. We propose an approach to $\mathrm{C}^*$-algebras associated to product systems over $P$. We call the $\mathrm{C}^*$-algebra of a given product system $\mathcal{E}$ its covariance algebra and…

Operator Algebras · Mathematics 2018-11-21 Camila F. Sehnem

Given a connected non-negative unit form we construct an extended affine Lie algebra by giving a Chevalley basis for it. We also obtain this algebra as a quotient of an algebra defined by means of generalized Serre relations by M. Barot, D.…

Representation Theory · Mathematics 2017-06-15 Gustavo Jasso

In this paper we define an explicit E_{infinity}-structure, i.e. a coherently homotopy associative and commutative product on chain complexes defining (integral and mod-l) motivic cohomology as well as mod -l \'etale cohomology. We also…

Algebraic Geometry · Mathematics 2014-07-22 Roy Joshua

We refine and advance the study of the local structure of idempotent finite algebras started in [A.Bulatov, The Graph of a Relational Structure and Constraint Satisfaction Problems, LICS, 2004]. We introduce a graph-like structure on an…

Logic in Computer Science · Computer Science 2016-01-28 Andrei A. Bulatov

Continual Lie algebras are infinite-dimensional generalizations of Lie algebras with discrete root system by considering continual root systems. In this paper we establish the general relation between chain complexes and continual Lie…

Functional Analysis · Mathematics 2026-05-20 A. Zuevsky

We consider infinite $\Z_\Z$-index complexes $\mathcal C$ of spaces with elements depending on a number of parameters, complete with respect to a linear associative regular inseparable multilinear product. The existence of nets of vanishing…

Functional Analysis · Mathematics 2026-03-06 Daniel Levin , Alexander Zuevsky

We investigate infinite-exponent partition relations on arbitrary relational structures, with a focus on linear orders and graphs. Any such relation contradicts the Axiom of Choice. We show that there are some such relations which are…

Logic · Mathematics 2026-05-22 Lyra A. Gardiner , Jonathan Schilhan

We review some recent results related to the self-assembly of infinite structures in the Tile Assembly Model. These results include impossibility results, as well as novel tile assembly systems in which shapes and patterns that represent…

Computational Complexity · Computer Science 2009-06-19 Matthew J. Patitz , Scott M. Summers

In the paper we prove for every finite algebra A that either it has the polynomially generated powers (PGP) property, or it has the exponentially generated powers (EGP) property. For idempotent algebras we give a simple criteria for the…

Rings and Algebras · Mathematics 2015-04-10 Dmitriy Zhuk

A garland based on a manifold $P$ is a finite set of manifolds homeomorphic to $P$ with some of them glued together at marked points. Fix a manifold $M$ and consider a space $\NN$ of all smooth mappings of garlands based on $P$ into $M$. We…

Geometric Topology · Mathematics 2007-05-23 Vladimir Chernov , Yuli. B. Rudyak

We prove a filtered version of the Homotopy Transfer Theorem which gives an A-infinity algebra structure on any page of the spectral sequence associated to a filtered dg-algebra. We then develop various applications to the study of the…

Algebraic Topology · Mathematics 2022-10-19 Joana Cirici , Anna Sopena

We show that the mapping cone of a morphism of differential graded Lie algebras $\chi\colon L\to M$ can be canonically endowed with an $L_\infty$-algebra structure which at the same time lifts the Lie algebra structure on $L$ and the usual…

Quantum Algebra · Mathematics 2013-09-30 Domenico Fiorenza , Marco Manetti