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Full-Text Articles in Physical Sciences and Mathematics

Behavior And Dynamics Of The Set Of Absolute Nilpotent And Idempotent Elements Of Chain Of Evolution Algebras Depending On The Time, Anvar Imomkulov Dec 2020

Behavior And Dynamics Of The Set Of Absolute Nilpotent And Idempotent Elements Of Chain Of Evolution Algebras Depending On The Time, Anvar Imomkulov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In this paper we construct some families of three-dimensional evolution algebras which satisfies Chapman-Kolmogorov equation. For all of these chains we study the behavior of the baric property, the behavior of the set of absolute nilpotent elements and dynamics of the set of idempotent elements depending on the time.


Some Properties Of A(Z)-Subharmonic Functions, Shohruh Khursanov Dec 2020

Some Properties Of A(Z)-Subharmonic Functions, Shohruh Khursanov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In this paper we give a definition of A(z)-subharmonic functions and consider some properties of A(z)-subharmonic functions. Namely A(z)-subharmonicity criterion in class C2.


The Fokas' Unified Transformation Method For Airy Equation On Simple Open Star Graph, Zarifboy Sobirov, Mardonbek Eshimbetov Dec 2020

The Fokas' Unified Transformation Method For Airy Equation On Simple Open Star Graph, Zarifboy Sobirov, Mardonbek Eshimbetov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

We considered the Airy equation on the simple star graph with three semi-infinite bonds. At the branching point of the graph we used second kind vertex conditions. Exact integral representation of the solution is obtained via Fokas unified transformation method.


The Ψ-Harmonic Measure And Its Properties, Nurbek Narzillaev, Kobiljon Kuldoshev Dec 2020

The Ψ-Harmonic Measure And Its Properties, Nurbek Narzillaev, Kobiljon Kuldoshev

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

It is known that, the harmonic measure of a set E, relative to a domain D, is defined by means of subharmonic functions on D. In this article we define a generalization of a harmonic measure and prove some of its properties.


Restoring The Function Set By Integrals For The Family Of Parabolas On The Plane, Akram Begmatov, Alisher Ismoilov Jun 2020

Restoring The Function Set By Integrals For The Family Of Parabolas On The Plane, Akram Begmatov, Alisher Ismoilov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

Integral geometry is one of the most important sections of the theory of ill-posed problems of mathematical physics and analysis. The urgency of the problems of integral geometry is due to the development of tomographic methods, which raise the requirements for the depth of the applied results, the fact that the solution of problems of integral geometry reduces a number of multidimensional inverse problems for partial differential problems, as well as the internal development needs of the theory of ill-posed problems of mathematical physics and analysis. In this work we consider the problem of reconstructing a function from a family …


Geometric Properties Of A-Harmonic Functions, Shokhrukh Khursanov Jun 2020

Geometric Properties Of A-Harmonic Functions, Shokhrukh Khursanov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

This paper is devoted to geometric properties of A(z)-harmonic functions and the corresponding Laplace operator Δ A(u). It is proved that the generalized A(z)-harmonic function is generated by the usual A(z)-harmonic function.


Damped Oscillatory Integrals And Weierstrass Polynomials, Azimbay Sadullaev, Isroil Ikromov, Shaxriddin Muranov Jun 2020

Damped Oscillatory Integrals And Weierstrass Polynomials, Azimbay Sadullaev, Isroil Ikromov, Shaxriddin Muranov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In this paper we consider the Sogge- Stein problem related to the damped oscillatory integrals. We show that in three-dimensional Euclidean spaces minimal exponent, which guarantees optimal decaying of the Fourier transform of the surfaces-carried measures with mitigating factor is bounded by 3/2. A proof of the main theorem is based on Weierstrass type results.


Generalized Metric Spaces And Hyperspaces, Ruzinazar Beshimov, Dilnora Safarova Jun 2020

Generalized Metric Spaces And Hyperspaces, Ruzinazar Beshimov, Dilnora Safarova

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In this paper, we investigate the heredity of some kind of generalized metric spaces to ecX and enX. We will study the connection between a σ-space, Σ-space, a stratifiable space, ℵ-space, ℵ0-space and its hyperspace.


Fractional Differentiation Of The Grunwald-Letnikov-Hadamard Type And The Difference Of The Fractional Order With A Multiplicative Step, Mahmadiyor Yakhshiboev Jun 2020

Fractional Differentiation Of The Grunwald-Letnikov-Hadamard Type And The Difference Of The Fractional Order With A Multiplicative Step, Mahmadiyor Yakhshiboev

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

The properties of ''convolution-type'' operators that are invariant with respect to dilation and to their approximation using a unity in weighted mixed Lebesgue spaces are studied in this paper. Integral representations are obtained for the Marchaud-Hadamard and Marchaud-Hadamard type truncated fractional derivatives (by direction and mixed ones). This paper introduces the concept of a mixed difference of a vector fractional order with a multiplicative step and its properties. Some of these properties are proven using the Mellin transform. In this paper, we give the proof of theorems on coincidence of the definition domains of two different forms of fractional differentiation …


The Symmetric Form Of A Poroelasticity System In Terms Of Velocities, Stresses And Pressure, Sayyora Tuychieva Jun 2020

The Symmetric Form Of A Poroelasticity System In Terms Of Velocities, Stresses And Pressure, Sayyora Tuychieva

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

The form for representing the equation of motion for porous media in terms of velocities, stresses, and pressure as a symmetric hyperbolic Friedrechs system has been obtained. A two-dimensional initial- boundary value problem in a half-space is considered, the excitation source is a point source. For its numerical solution, an explicit predictor-corrector scheme is used. A series of numerical calculations for a test model of media is presented.


The Entrance Times For Circle Maps With A Break, Akhtam Dzhalilov, Javlon Karimov Jun 2020

The Entrance Times For Circle Maps With A Break, Akhtam Dzhalilov, Javlon Karimov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In present work we study the entrance times for circle homeomorphisms with one break point and universal renormalization properties. Consider the set X of all orientation preserving circle homeomorphisms T with one break point and golden mean rotation number. It is well known that the renormalization group transformation has a unique periodic point T b with period 2. Denote by B the set of all circle maps C1 -conjugated to T b . Consider the map T ∈ B and its unique probability invariant measure μ . Denote by E(x) the first entrance times of x to interval defined …


The Method Of Potentials For The Airy Equation Of Fractional Order, Kamoliddin Rakhimov Jun 2020

The Method Of Potentials For The Airy Equation Of Fractional Order, Kamoliddin Rakhimov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In this work initial-boundary value problems for time-fractional Airy equation are considered on the different intervals. We studied properties of potentials for this equation and using these properties found the solutions of the considered problems. The uniqueness of problems proved using the analogue of Grö nwall–Bellman inequality and apriory estimate.


On The Application Of Multidimensional Logarithmic Residue To Systems Of Non-Algebraic Equations, Barlikbay Prenov Apr 2020

On The Application Of Multidimensional Logarithmic Residue To Systems Of Non-Algebraic Equations, Barlikbay Prenov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In this paper, the residue integrals over cycles associated with a system of non-algebraic equations and formulas for their calculation are given. Their connection with the power sums of the roots of the system is established. Some examples are considered.


Jump Theorems For The Bochner-Martinelli Integral In Domains With A Piecewise Smooth Boundary, Alexander Kytmanov, Davlatbay Dzhumabaev, Bayrambay Utemuratov, Barlikbay Prenov Feb 2020

Jump Theorems For The Bochner-Martinelli Integral In Domains With A Piecewise Smooth Boundary, Alexander Kytmanov, Davlatbay Dzhumabaev, Bayrambay Utemuratov, Barlikbay Prenov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

Jump theorems for the Bochner-Martinelli integral in domains with a piecewise smooth boundary are obtained. Moreover, theorem for the Bochner-Martinelli integral in domains with a piecewise smooth boundary is proved for continuous functions and also for functions from the class 𝓛p.