Deformation Of Algebra Research Articles

Cocycle deformations for Hom-Hopf algebras

In this paper we introduce the Hom-analogue of the definition of 2-cocycle for Hopf algebras, called Hom-2-cocycle, and study its properties in order to give a theory of multiplication alteration by Hom-2-cocycles for Hom-Hopf algebras. We show that, just like in the classical setting, if H is a Hom-Hopf algebra with associated endomorphism α and σ is a convolution invertible Hom-2-cocycle, it is possible to define a new product in H to get a new Hom-Hopf algebra if α4=α. Moreover we introduce the notions of matched pair and skew pairing in the Hom case and, by the close connection between Hom-2-cocycles and Hom-skew pairings, we show that a special case of Hom-matched pair can be obtained as a deformation of a Hom-Hopf algebra by a Hom-2-cocycle built by a Hom-skew pairing.

Superfiltered A∞$A_\infty$‐deformations of the exterior algebra, and local mirror symmetry

The exterior algebra $E$ on a finite-rank free module $V$ carries a $\mathbb{Z}/2$-grading and an increasing filtration, and the $\mathbb{Z}/2$-graded filtered deformations of $E$ as an associative algebra are the familiar Clifford algebras, classified by quadratic forms on $V$. We extend this result to $A_\infty$-algebra deformations $\mathcal{A}$, showing that they are classified by formal functions on $V$. The proof translates the problem into the language of matrix factorisations, using the localised mirror functor construction of Cho-Hong-Lau, and works over an arbitrary ground ring. We also compute the Hochschild cohomology algebras of such $\mathcal{A}$. By applying these ideas to a related construction of Cho-Hong-Lau we prove a local form of homological mirror symmetry: the Floer $A_\infty$-algebra of a monotone Lagrangian torus is quasi-isomorphic to the endomorphism algebra of the expected matrix factorisation of its superpotential.

Boundary Heisenberg algebras and their deformations

We investigate the deformations and rigidity of boundary Heisenberg-like algebras. In particular, we focus on the Heisenberg and Heisenberg ⊕ mathfrak{witt} algebras which arise as symmetry algebras in three-dimensional gravity theories. As a result of the deformation procedure we find a large class of algebras. While some of these algebras are new, some of them have already been obtained as asymptotic and boundary symmetry algebras, supporting the idea that symmetry algebras associated to diverse boundary conditions and spacetime loci are algebraically interconnected through deformation of algebras. The deformation/contraction relationships between the new algebras are investigated. In addition, it is also shown that the deformation procedure reaches new algebras inaccessible to the Sugawara construction. As a byproduct of our analysis, we obtain that Heisenberg ⊕ mathfrak{witt} and the asymptotic symmetry algebra Weyl-bms3 are not connected via single deformation but in a more subtle way.

The hom-associative Weyl algebras in prime characteristic

We introduce the first hom-associative Weyl algebras over a field of prime characteristic as a generalization of the first associative Weyl algebra in prime characteristic. First, we study properties of hom-associative algebras constructed from associative algebras by a general ``twisting'' procedure. Then, with the help of these results, we determine the commuter, center, nuclei, and set of derivations of the first hom-associative Weyl algebras. We also classify them up to isomorphism, and show, among other things, that all nonzero endomorphisms on them are injective, but not surjective. Last, we show that they can be described as a multi-parameter formal hom-associative deformation of the first associative Weyl algebra, and that this deformation induces a multi-parameter formal hom-Lie deformation of the corresponding Lie algebra, when using the commutator as bracket.

On the Heisenberg algebra associated with the rational R-matrix

We associate a deformation of the Heisenberg algebra with the suitably normalized Yang R-matrix, and we investigate its properties. Moreover, we construct new examples of quantum vertex algebras, which possess the same representation theory as the aforementioned deformed Heisenberg algebra.

On Hom-F-manifold algebras and quantization

The notion of a $F$-manifold algebras is an algebraic description of a $F$-manifold. In this paper, we introduce the notion of Hom-$F$-manifold algebras which is generalisation of $F$-manifold algebras and Hom-Poisson algebras. We develop the representation theory of Hom-$F$-manifold algebras and generalize the notion of Hom-pre-Poisson algebras by introducing the Hom-pre-$F$-manifold algebras which give rise to a Hom-$F$-manifold algebra through the subadjacent commutative Hom-associative algebra and the subadjacent Hom-Lie algebra. Using Ο-operators on a Hom-$F$-manifold algebras we construct a Hom-pre-$F$-manifold algebras on a module. Then, we study Hom-pre-Lie formal deformations of commutative Hom-associative algebra and we prove that Hom-$F$-manifold algebras are the corresponding semiclassical limits. Finally, we study Hom-Lie infinitesimal deformations and extension of Hom-pre-Lie $n$-deformation to Hom-pre-Lie $(n+1)$-deformation of a commutative Hom-associative algebra via cohomology theory.

Deformation and Hochschild cohomology of coisotropic algebras

Coisotropic algebras consist of triples of algebras for which a reduction can be defined and unify in a very algebraic fashion coisotropic reduction in several settings. In this paper, we study the theory of (formal) deformation of coisotropic algebras showing that deformations are governed by suitable coisotropic DGLAs. We define a deformation functor and prove that it commutes with reduction. Finally, we study the obstructions to existence and uniqueness of coisotropic algebras and present some geometric examples.

A gravitational action with stringy Q and R fluxes via deformed differential graded Poisson algebras

We study a deformation of a 2-graded Poisson algebra where the functions of the phase space variables are complemented by linear functions of parity odd velocities. The deformation is carried by a 2-form B-field and a bivector Π, that we consider as gauge fields of the geometric and non-geometric fluxes H, f, Q and R arising in the context of string theory compactification. The technique used to deform the Poisson brackets is widely known for the point particle interacting with a U(1) gauge field, but not in the case of non-abelian or higher spin fields. The construction is closely related to Generalized Geometry: with an element of the algebra that squares to zero, the graded symplectic picture is equivalent to an exact Courant algebroid over the generalized tangent bundle E ≅ TM ⊕ T∗M, and to its higher gauge theory. A particular idempotent graded canonical transformation is equivalent to the generalized metric. Focusing on the generalized differential geometry side we construct an action functional with the Ricci tensor of a connection on covectors, encoding the dynamics of a gravitational theory for a contravariant metric tensor and Q and R fluxes. We also extract a connection on vector fields and determine a non-symmetric metric gravity theory involving a metric and H-flux.

Structural losses, structural realism and the stability of Lie algebras

One of the key assumptions associated with structural realism is the claim that successful scientific theories approximately preserve their structurally based content as they are progressively developed and that this content alone can explain their relevant predictions. The precise way in which these theories are preserved is not trivial but, according to this realist thesis, any kind of structural loss should not occur among theoretical transitions. Although group theory has been proven effective in accounting for preserved structures in the context of physics, structural realists are confronted with the fact that even group-theoretic structures are not immune to these structural discontinuities. Under such circumstances, my contribution consists in a two-fold task. Firstly, I will establish a general condition at the level of the group-theoretic structure to avoid the pessimistic induction argument by appealing to Lie algebra deformation and stability theory; and secondly, I will provide a case study associated with quantum-relativistic kinematics to demonstrate that this condition is actually satisfied. Specifically, through this case study I will support the claim that if the full Lie algebras of our current successful theories are stable, it is possible to disregard any kind of structural loss in the future and explain the relevant successful predictions in a way that we can support structural realism accordingly.

Cohomology and deformations of BiHom-Lie conformal algebras

In this paper, we introduce the notion of BiHom-Lie conformal algebras and develop the cohomology theory.Furthermore, we discuss the deformations of regular BiHom-Lie conformal algebras and present some applications. Finally, we introduce derivations of BiHom-Lie conformal algebras and study their properties.

K-theoretic Hall algebras, quantum groups and super quantum groups

We prove that the K-theoretic Hall algebra of a preprojective algebra of affine type is isomorphic to the positive half of a quantum toroidal quantum group. We also compare super toroidal quantum groups of type A with some K-theoretic Hall algebras of quivers with potential introduced recently by Padurariu using categories of singularities of some Landau–Ginzburg models. The proof uses both a deformation of the K-theoretic Hall algebra and a dimensional reduction which allows us to compare the KHA of preprojective algebras to the K-theoretic Hall algebras of a quiver with potential.

3-dimensional \u039b-BMS symmetry and its deformations

In this paper we study quantum group deformations of the infinite dimensional symmetry algebra of asymptotically AdS spacetimes in three dimensions. Building on previous results in the finite dimensional subalgebras we classify all possible Lie bialgebra structures and for selected examples we explicitely construct the related Hopf algebras. Using cohomological arguments we show that this construction can always be performed by a so-called twist deformation. The resulting structures can be compared to the well-known κ-Poincaré Hopf algebras constructed on the finite dimensional Poincaré or (anti) de Sitter algebra. The dual κ Minkowski spacetime is supposed to describe a specific non-commutative geometry. Importantly, we find that some incarnations of the κ-Poincaré can not be extended consistently to the infinite dimensional algebras. Furthermore, certain deformations can have potential physical applications if subalgebras are considered. Since the conserved charges associated with asymptotic symmetries in 3-dimensional form a centrally extended algebra we also discuss briefly deformations of such algebras. The presence of the full symmetry algebra might have observable consequences that could be used to rule out these deformations.

On deformations of the Galilei algebra

In this note we compute all deformations of the 4-dimensional classical Galilei algebra &. In particular, we find examples of quadratic, cubic and quartic Lie algebra deformations.

Semisimplicity of the Deformations of the Subcharacter Algebra of an Abelian Group

For those deformations that satisfy a certain non-degeneracy condition, we describe the structure of certain simple modules of the deformations of the subcharacter algebra of a finite group. For finite abelian groups, we prove that the deformation given by the inclusion of the natural numbers, which corresponds to the algebra generated by the fibred bisets over a field of characteristic zero, is not semisimple. In the cyclic group of prime order case, we provide a complete description of the semisimple deformations.

3D gravity in a box

The quantization of pure 3D gravity with Dirichlet boundary conditions on a finite boundary is of interest both as a model of quantum gravity in which one can compute quantities which are ``more local" than S-matrices or asymptotic boundary correlators, and for its proposed holographic duality to T\overline{T}TT¯-deformed CFTs. In this work we apply covariant phase space methods to deduce the Poisson bracket algebra of boundary observables. The result is a one-parameter nonlinear deformation of the usual Virasoro algebra of asymptotically AdS_33 gravity. This algebra should be obeyed by the stress tensor in any T\overline{T}TT¯-deformed holographic CFT. We next initiate quantization of this system within the general framework of coadjoint orbits, obtaining — in perturbation theory — a deformed version of the Alekseev-Shatashvili symplectic form and its associated geometric action. The resulting energy spectrum is consistent with the expected spectrum of T\overline{T}TT¯-deformed theories, although we only carry out the explicit comparison to \mathcal{O}(1/\sqrt{c})𝒪(1/c) in the 1/c1/c expansion.

Extensions and Deformations of Algebras with Higher Derivations

Higher derivations on an associative algebra generalize higher-order derivatives. We call a tuple consisting of an algebra and a higher derivation on it by an AssHDer pair. We define cohomology for AssHDer pairs with coefficients in a representation. Next, we study central extensions of an AssHDer pair and relate them with the second cohomology group of the AssHDer pair. Finally, we consider deformations of AssHDer pairs that are governed by the cohomology with self-coefficient.

Cohomology and deformations of dendriform algebras, and Dend∞-algebras

A dendriform algebra is an associative algebra whose product splits into two binary operations and the associativity splits into three new identities. These algebras arise naturally from some combinatorial objects and through Rota-Baxter operators. In this paper, we start by defining explicit cohomology of dendriform algebras with coefficients in a representation. Our method avoids the heavy use of operad theory. Deformations of a dendriform algebra A are governed by the cohomology of A with coefficient in itself. Next, we study -algebras (dendriform algebras up to homotopy) in which the dendriform identities hold up to certain homotopy. They are a certain splitting of -algebras. We define Rota-Baxter operator on -algebras which naturally gives rise to -algebras. Finally, we classify skeletal and strict -algebras.

Membership Deformation of Commutativity and Obscure n-ary Algebras

A general mechanism for "breaking" commutativity in algebras is proposed: if the underlying set is taken to be not a crisp set, but rather an obscure/fuzzy set, the membership function, reflecting the degree of truth that an element belongs to the set, can be incorporated into the commutation relations. The special "deformations" of commutativity and $\varepsilon $-commutativity are introduced in such a way that equal degrees of truth result in the "nondeformed" case. We also sketch how to "deform" $\varepsilon$-Lie algebras and Weyl algebras. Further, the above constructions are extended to $n$-ary algebras for which the projective representations and $\varepsilon $-commutativity are studied.

Underlying SUSY in a generalized Jaynes\u2013Cummings model

We present a general qubit-boson interaction Hamiltonian that describes the Jaynes–Cummings model and its extensions as a single Hamiltonian class. Our model includes non-linear processes for both the free qubit and boson field as well as non-linear, multi-boson excitation exchange between them. It shows an underlying algebra with supersymmetric quantum mechanics features allowing an operator based diagonalization that simplifies the calculations of observables. As a practical example, we show the evolution of the population inversion and the boson quadratures for an initial state consisting of the qubit in the ground state interacting with a coherent field for a selection of cases covering the standard Jaynes–Cummings model and some of its extensions including Stark shift, Kerr-like, intensity dependent coupling, multi-boson exchange and algebraic deformations.

Deformations of Lie algebras of Type Dn and Their Factoralgebras over the Field of Characteristic 2

Deformations of Lie algebras of Type Dn and Their Factoralgebras over the Field of Characteristic 2