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B. A. Omirov

Publications and source records attributed to B. A. Omirov.

At least 19 recordsLinked to original sources
arXiv2026

Non-Linear Generalization of the DLR Equations: $q$-Specifications and $q$-Equilibrium Measures

We introduce a {\it non-linear} generalization of the classical Dobrushin-Lanford-Ruelle (DLR) framework by developing the concept of a $q$-specification and the associated $q$-equilibrium measures. These objects arise naturally from a family of non-linear $q$-stochastic operators acting on the space of probability measures. A $q$-equilibrium measure is characterized as a fixed point of such operators, providing a non-linear analogue of the Gibbs equilibrium in the sense of DLR. We establish general conditions ensuring the existence and uniqueness of $q$-equilibrium measures and demonstrate how quasilocality plays a decisive role in their construction. Moreover, we exhibit examples of $q$-specifications with an empty set of $q$-equilibrium measures. We characterize the set of $q$-equilibrium measures by studying the dynamical systems generated by a class of $q$-stochastic operators. As a concrete application, we show that for the one-dimensional Ising model at sufficiently low temperatures, multiple $q$-equilibrium measures may exist, even though the classical Gibbs measure remains unique. Our results reveal that the $q$-specification formalism extends the DLR theory from linear to non-linear settings and opens a new direction in the study of Gibbs measures and equilibrium states of physical systems.

math-ph↗
arXiv2026

Solvable compatible Lie algebras with a given nilradical

We extend the classical construction of solvable Lie algebras from a nilradical to compatible Lie algebras. Since the sum of nilpotent ideals may fail to be nilpotent, we replace the usual nilradical by a \emph{special nilradical} that behaves well with the mixed Jacobi identity. We use the maximal tori of diagonal derivations to build solvable extensions. The method is applied to the pairs $(\mathrm L_n,\mathrm R_n)$ and $(\mathrm L_n,\mathrm W_n)$, yielding explicit one-dimensional solvable extensions and proving nonexistence of higher-dimensional ones in these cases. We also study filiform compatible Lie algebras. We introduce the model family $\mathcal L_s$ and show that each $\mathcal L_s$ is a linear deformation of the model filiform Lie algebra $\mathcal L_k$. Finally, we study the existence of solvable extensions of this family, within the framework developed above.

math.RA↗
arXiv2026

Cohomological rigidity of solvable Lie algebras of maximal ran

We study the second cohomology group with coefficients in the adjoint module for a class of solvable Lie algebras $\mathcal{R}_{\mathcal{T}}$ that arise as maximal solvable extensions of nilpotent Lie algebras $\mathcal{N}$ of maximal rank. Under suitable structural assumptions on the root system determined by the action of a maximal torus $\mathcal{T}$ on $\mathcal{N}$, we obtain sufficient conditions for the cohomological rigidity of $\mathcal{R}_{\mathcal{T}}$. Conversely, we identify explicit configurations of roots that force the second cohomology group to be non-trivial, thereby producing broad families of solvable Lie algebras that are not cohomologically rigid. Our results extend the classical sufficient conditions of Leger and Luks, and they provide a unified and computationally effective framework for determining the cohomological rigidity of a wide class of solvable Lie algebras, including several known results.

math.RA↗
arXiv2025

Infinite dimensional analogues of nilpotent and solvable Lie algebras

We study infinite-dimensional analogues of nilpotent and solvable Lie algebras, focusing on the classes of pro-nilpotent, residually nilpotent, pro-solvable and residually solvable Lie algebras. We extend classical triangularization results (Engel's and Lie's theorems) to the pro-setting and establish existence results for the pro-nilpotent radical in pro-solvable algebras and in certain residually solvable algebras. We adapt finite-dimensional construction methods to produce residually solvable extensions with a given pro-nilpotent radical under natural finiteness conditions. By analyzing derivations and maximal tori of pro-nilpotent algebras, we extend the notion of rank and show that, for pro-nilpotent algebras of maximal rank, every derivation of a maximal residually solvable extension is inner. Finally, we describe standard constructions (tensor and direct sum products, central extensions) that preserve pro-nilpotency.

math.RA↗
arXiv2025

Coupled Ising-Potts Model: Rich Sets of Critical Temperatures and Translation-Invariant Gibbs Measures

We consider a coupled Ising-Potts model on Cayley trees of order $ k \geq 2 $. This model involves spin vectors $ (s, σ) $, and generalizes both the Ising and Potts models by incorporating interactions between two types of spins: $s = \pm 1$ and $σ= 1, \dots, q$. It is applicable to a wide range of systems, including multicomponent alloys, spin glasses, biological systems, networks, and social models. In this paper, we find some translation-invariant splitting Gibbs measures (TISGMs) and show, for $k\geq 2$, that at sufficiently low temperatures, the number of such measures is at least $2^{q}+1$. This is not an exact upper bound; for $k=2$ and $q=5$, we demonstrate that the number of TISGMs reaches the exact bound of 335, which is much larger than $2^5+1=33$. We prove, for $q=5$ that there are 12 critical temperatures at which the number of TISGMs changes, and we provide the exact number of TISGMs for each intermediate temperature. Additionally, we identify temperature regions where three TISGMs, close to the free measure, are either extreme or non-extreme among all Gibbs measures. We also show that the coupled Ising-Potts model exhibits properties absent in the individual Ising and Potts models. In particular, we observe the following new phenomena: 1. In both the Ising and Potts models, if a Gibbs measure exists at some temperature $T_0$, then it exists for all $T<T_0$. However, in the coupled Ising-Potts model, some TISGMs may only exist at intermediate temperatures (neither very low nor very high). 2. The 5-state Potts model has three critical temperatures and up to 31 TISGMs. We show that for $q=5$, the coupled Ising-Potts model has four times as many critical temperatures and approximately 11 times as many TISGMs. Thus, our model modifies the phase structure more rapidly and exhibits a significantly richer class of splitting Gibbs measures.

math.FA↗
arXiv2024

A many-loci system with evolution characterized by uncountable linear operators

This paper investigates the evolution of a multi-locus biological system. The evolution of such a system is described by a quadratic stochastic operator (QSO) defined on a simplex. We demonstrate that this QSO can be decomposed into an infinite series of linear operators, each of which maps certain invariant subsets of the simplex to themselves. Furthermore, the entire simplex is the union of these invariant subsets, enabling analytical examination of the dynamical systems produced by the QSO. Finding all limit points of the dynamical system generated by the QSO in terms of the limit points of the linear operators, we provide a comprehensive characterization of the many-loci population dynamics.

math.DS↗
arXiv2024

2D Moore CA with new boundary conditions and its reversibility

In this paper, under certain conditions we consider two-dimensional cellular automata with the Moore neighborhood. Namely, the characterization of 2D linear cellular automata defined by the Moore neighborhood with some mixed boundary conditions over the field $\mathbb{Z}_{p}$ is studied. Furthermore, we investigate the rule matrices of 2D Moore CA under some mixed boundary conditions by applying rotation. Finally, we give the conditions under which the obtained rule matrices for 2D finite CAs are reversible.

math.DS↗
arXiv2022

On maximal solvable extensions of a pure non-characteristically nilpotent Lie algebra

In this paper we introduce the notion of pure non-characteristically nilpotent Lie algebra and under a condition we prove that a complex maximal extension of a finite-dimensional pure non-characteristically nilpotent Lie algebra is isomorphic to a semidirect sum of the nilradical and its maximal torus. We also prove that such solvable Lie algebras are complete and we specify a subclass of the maximal solvable extensions of pure non-characteristically nilpotent Lie algebras that have trivial cohomology group. Some comparisons with the results obtained earlier are given.

math.RA↗
arXiv2022

On some solvable Leibniz algebras and their completeness

The paper is devoted studying solvable Leibniz algebras with a nilradical possessing the codimension equals the number of its generators. We describe this class in non-split nilradical case. Then the case of split nilradical is worked out. We show that the results obtained earlier on this class of Leibniz algebras come as particular cases of the results of this paper. It is shown that such a solvable extension is unique. Finally, we prove that the solvable Leibniz algebras considered are complete.

math.RA↗
arXiv2020

On Solvable Lie and Leibniz Superalgebras with maximal codimension of nilradical

Along this paper we show that under certain conditions the method for describing of solvable Lie and Leibniz algebras with maximal codimension of nilradical is also extensible to Lie and Leibniz superalgebras, respectively. In particular, we totally determine the solvable Lie and Leibniz superalgebras with maximal codimension of model filiform and model nilpotent nilradicals. Finally, it is established that the superderivations of the obtained superalgebras are inner.

math.RA↗
arXiv2019

Solvable Leibniz algebras with naturally graded non-Lie $p$-filiform nilradicals and maximal complemented space of its nilradical

The present article is a part of the study of solvable Leibniz algebras with a given nilradical. In this paper solvable Leibniz algebras, whose nilradicals is naturally graded $p$-filiform non-Lie Leibniz algebra $(n-p\geq4)$ and the complemented space to nilradical has maximal dimension, are described up to isomorphism. Moreover, among obtained algebras we indicate the rigid and complete algebras

math.RA↗
arXiv2018

Leibniz algebras constructed by Witt algebras

We describe infinite-dimensional Leibniz algebras whose associated Lie algebra is the Witt algebra and we prove the triviality of low-dimensional Leibniz cohomology groups of the Witt algebra with the coefficients in itself.

math.RA↗
arXiv2017

A class of nilpotent evolution algebras

Recently, by A. Elduque and A. Labra a new technique and a type of an evolution algebra are introduced. Several nilpotent evolution algebras defined in terms of bilinear forms and symmetric endomorphisms are constructed. The technique then used for the classification of the nilpotent evolution algebras up to dimension five. In this paper we develop this technique for high dimensional evolution algebras. We construct nilpotent evolution algebras of any type. Moreover, we show that, except the cases considered by Elduque and Labra, this construction of nilpotent evolution algebras does not give all possible nilpotent evolution algebras.

math.RA↗
arXiv2016

Leibniz algebras associated with representations of Euclidean Lie algebra

In the present paper we describe Leibniz algebras with three-dimensional Euclidean Lie algebra $\mathfrak{e}(2)$ as its liezation. Moreover, it is assumed that the ideal generated by the squares of elements of an algebra (denoted by $I$) as a right $\mathfrak{e}(2)$-module is associated to representations of $\mathfrak{e}(2)$ in $\mathfrak{sl}_2({\mathbb{C}})\oplus \mathfrak{sl}_2({\mathbb{C}}), \mathfrak{sl}_3({\mathbb{C}})$ and $\mathfrak{sp}_4(\mathbb{C})$. Furthermore, we present the classification of Leibniz algebras with general Euclidean Lie algebra ${\mathfrak{e(n)}}$ as its liezation $I$ being an $(n+1)$-dimensional right ${\mathfrak{e(n)}}$-module defined by transformations of matrix realization of $\mathfrak{e(n)}.$ Finally, we extend the notion of a Fock module over Heisenberg Lie algebra to the case of Diamond Lie algebra $\mathfrak{D}_k$ and describe the structure of Leibniz algebras with corresponding Lie algebra $\mathfrak{D}_k$ and with the ideal $I$ considered as a Fock $\mathfrak{D}_k$-module.

math.RT↗