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Stability and Error Estimates of High Order BDF-LDG Discretizations for the Allen–Cahn Equation Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 Fengna Yan, Ziqiang Cheng
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Singularity Formation in an Incompressible Boundary Layer on an Upstream Moving Wall under Given External Pressure Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 S. I. Bezrodnykh, V. B. Zametaev, Te Ha Chzhun
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Generalization of the Penalized Wall Function Method for Modeling of Turbulent Flows with Adverse Pressure Gradient Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 O. V. Vasilyev, N. S. Zhdanova
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On the Simulation of a Rarefied Plasma Jet on the Basis of Kinetic Equations Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 M. V. Abgaryan, A. M. Bishaev, V. A. Rykov
Abstract The problem of a rarefied plasma jet emerging from a stationary plasma engine is considered. The consideration is carried out entirely at the kinetic level; namely, the motion of all plasma components is described in terms of distribution functions. The system of kinetic equations should be solved together with Maxwell’s equations. Methods for solving the resulting problem are discussed.
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Data Parallelization Algorithms for the Direct Simulation Monte Carlo Method for Rarefied Gas Flows on the Basis of OpenMP Technology Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 N. Yu. Bykov, S. A. Fyodorov
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A Novel Fitted Method for a Class of Singularly Perturbed Differential-Difference Equations with Small Delay Exhibiting Twin Layer or Oscillatory Behaviour Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 Mohammad Javed Alam, Hari Shankar Prasad, Rakesh Ranjan
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Accelerating the Solution of the Boltzmann Equation by Controlling Contributions to the Collision Integral Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 F. G. Tcheremissine
Abstract A method of reducing the number of arithmetic operations needed to evaluate the Boltzmann collision integral by the conservative projection method is proposed. This is achieved by eliminating the contributions that are less than a certain threshold. An estimate of the maximum magnitude of this threshold is given. For four such thresholds that differ by an order of magnitude from each other
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Study of Nonclassical Transport by Applying Numerical Methods for Solving the Boltzmann Equation Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 V. V. Aristov, I. V. Voronich, S. A. Zabelok
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Multipole Representation of the Gravitational Field of the Asteroid (16) Psyche Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 V. I. Nikonov
Abstract An approach to calculating multipole approximations of the gravitational potential of small celestial bodies with an irregular mass distribution is demonstrated for the asteroid (16) Psyche as an example.
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Nonclassical Heat Transfer in a Microchannel and a Problem for Lattice Boltzmann Equations Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 O. V. Ilyin
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Study of the Gardner Equation with Homogeneous Boundary Conditions via Fourth Order Modified Cubic B-Spline Collocation Method Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 S. Dahiya, A. Singh, S. P. Singh
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Numerical Analysis of Rarefied Gas Flow through a System of Short Channels Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 I. V. Voronich, V. A. Titarev
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Projection-Grid Schemes on Irregular Grids for a Parabolic Equation Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 O. G. Olkhovskaya
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Stability Analysis of Polymerization Fronts Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2024-01-29 Y. Joundy, H. Rouah, A. Taik
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Formulas for Computing Euler-Type Integrals and Their Application to the Problem of Constructing a Conformal Mapping of Polygons Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 S. I. Bezrodnykh
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Solving Nonlinear Volterra Integral Equations of the First Kind with Discontinuous Kernels by Using the Operational Matrix Method Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 Simin Aghaei Amirkhizi, Yaghoub Mahmoudi, Ali Salimi Shamloo
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On Numerical Beamforming for Correlated Dipole-Type Sources Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 T. K. Kozubskaya, G. M. Plaksin, I. L. Sofronov
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Exact Solutions of a Nonlinear Equation Describing Blow-Up Instability in Self-Oscillatory Systems Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 A. I. Aristov
Abstract A nonclassical fourth-order partial differential equation describing blow-up instability in self-oscillatory systems is studied. Several classes of exact solutions of this equation are constructed. It is shown that these solutions include ones growing to infinity in a finite time, ones bounded globally in time, and ones bounded on any finite time interval, but not globally.
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Blow-Up of the Solution to the Equation for Nonlinear Beam Vibrations with Allowance for Transverse Deformation Effects Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 Kh. G. Umarov
Abstract Beam vibrations with allowance for deformation effects in the transverse direction are modeled using a nonlinear Sobolev-type differential equation, for which the Cauchy problem is investigated in the space of continuous functions. Conditions for solution blow-up on a finite time interval are considered.
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Triple Series Evaluated in π and $$\ln 2$$ as Well as Catalan’s Constant G Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 Chunli Li, Wenchang Chu
Abstract By computing definite integrals, several infinite triple series are explicitly evaluated in terms of \(\pi \) and \(\ln 2\) as well as Catalan’s constant \(G\).
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An Approach to the Implementation of the Multigrid Method with Full Approximation for CFD Problems Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 A. V. Gorobets
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Analyticity and Pseudo-Analyticity in the Small Parameter Method Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 V. I. Kachalov, D. A. Maslov
Abstract The small parameter method allows one to construct solutions of differential equations in the form of power series and has become widespread in mathematical physics. In most cases, these series are asymptotically convergent. The aim of this work is to find conditions for the ordinary convergence of series in powers of a small parameter representing solutions of perturbation theory problems
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On a Particular Solution of the σ-Commutation Problem ( $$\sigma \ne 0, \pm 1$$ ) for Toeplitz and Hankel Matrices Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 V. N. Chugunov, Kh. D. Ikramov
A unified approach is proposed to the construction of matrix pairs \((T,H)\) that solve the \(\sigma \)‑commutation problem for Toeplitz and Hankel matrices. For a certain particular case, a family of solutions is derived.
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Discontinuity Structures and Solitary Waves in Electromagnetic Hydrodynamics Associated with Linear and Nonlinear Alfvén Wave Resonances Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 I. B. Bakholdin
Abstract Nondissipative and weakly dissipative discontinuity structures are considered. A special numerical method for studying periodic waves is used. The location of branches of periodic solutions is investigated. Solitary waves and nondissipative discontinuity structures are sought as limiting solutions. It is found that, in addition to the resonance of long Alfvén waves with short fast and slow
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Modeling the Motion of an Elongated Contour under Free Surface of a Heavy Fluid under Large Froude Numbers Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 S. I. Filippov
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Three-Level Schemes with Double Change in the Time Step Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 P. N. Vabishchevich
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Differential-Difference Equations with Optimal Parameters Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 A. F. Mastryukov
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A Fast Single-Pass Method for Solving the Generalized Eikonal Equation in a Moving Medium Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 M. S. Ho, J. S. Pak
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Analysis of the Influence of Quantum Effects on Optical Characteristics of Plasmonic Nanoparticles Based on the Discrete Sources Method Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 Yu. A. Eremin, V. V. Lopushenko
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On Weak Solvability of a Flow Problem for Viscoelastic Fluid with Memory Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 V. G. Zvyagin, V. P. Orlov
Abstract The existence of weak solutions of the initial-boundary value problem for the equations of motion of a viscoelastic fluid with memory along trajectories of a nonsmooth velocity field and with an inhomogeneous boundary condition is proved. The study relies on Galerkin-type approximations of the original problem followed by passage to the limit based on a priori estimates. The theory of regular
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Soft Computing Artificial Intelligence of Schrödinger Time Independent Equation Arises in Wheeler–DeWitt Model of Quantum Cosmology Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 Najam Ul Basat, Mahmoona Asghar
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Controlling Chaos in 3D Porous Media in the Presence of Orientation Effect Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-25 H. Rouah, Y. Joundy, A. Taik
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Numerical and Theoretical Analysis of Model Equations for Multicomponent Rarefied Gas Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-01
Abstract Model equations approximating the system of Boltzmann equations for a multicomponent gas are investigated. Methods for determining parameters in relaxation terms corresponding to cross-collision integrals are analyzed. Numerical solutions based on three model systems and the Boltzmann equations are compared as applied to the following problems: relaxation of a mixture to equilibrium, shock
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Evolution of the Shape of a Gas Cloud during Pulsed Laser Evaporation into Vacuum: Direct Simulation Monte Carlo and the Solution of a Model Equation Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-01
Abstract The dynamics of gas expansion during nanosecond laser evaporation into vacuum is studied. The problem is considered in an axisymmetric formulation for a wide range of parameters: the number of evaporated monolayers and the size of the evaporation spot. To obtain a reliable numerical solution, two different kinetic approaches are used—the direct simulation Monte Carlo method and solution of
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A Uniformly Convergent Numerical Method for Singularly Perturbed Semilinear Integro-Differential Equations with Two Integral Boundary Conditions Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-01
Abstract This paper purposes to present a new discrete scheme for the singularly perturbed semilinear Volterra–Fredholm integro-differential equation including two integral boundary conditions. Initially, some analytical properties of the solution are given. Then, using the composite numerical integration formulas and implicit difference rules, the finite difference scheme is established on a uniform
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On One Method for Calculating Nonstationary Heat Transfer between a Gas Flow and a Solid Body Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-01
Abstract A method for calculating the nonstationary thermal interaction between a viscous gas flow and a solid body is presented. The method consists in direct joint integration over time of the equations of gas dynamics of a multicomponent mixture and the heat equation in a solid on multi-block unstructured meshes. To calculate one time step, the system of governing equations is split into hyperbolic
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Density Function-Based Trust Region Algorithm for Approximating Pareto Front of Black-Box Multiobjective Optimization Problems Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-01
Abstract In this paper, we consider a black-box multiobjective optimization problem, whose objective functions are computationally expensive. We propose a density function-based trust region algorithm for approximating the Pareto front of this problem. At every iteration, we determine a trust region and then in this trust region, select several sample points, at which are evaluated objective function
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Analysis of Defects and Harmonic Grid Generation in Domains with Angles and Cutouts Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-12-01
Abstract A survey of works concerning difficulties associated with harmonic grid generation in plane domains with angles and cutouts is given, and some new results are presented. It is well known that harmonic grids produced by standard methods in domains with cutouts or reentrant angles (i.e., interior angles greater than π) may contain defects, such as self-overlappings or exit beyond the domain
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Coordinated Control of Multiple Surface Unmanned Vehicle Clusters under the Influence of Wind Field and Tides Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 Yanshan Liu, Zhiqing Dang, Zhaopeng Dai, Xinran Hao, Yan Cui, Hongwei Gao
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A Novel Uniform Numerical Approach to Solve a Singularly Perturbed Volterra Integro-Differential Equation Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 M. Cakir, E. Cimen
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Stability Analysis of Several Time Discrete Schemes for Allen–Cahn and Cahn–Hilliard Equations Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 Qiaoling He, Junping Yan, Abudurexiti Abuduwaili
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Boundary and Contact Conditions of Higher Order of Accuracy for Grid-Characteristic Schemes in Acoustic Problems Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 A. V. Shevchenko, V. I. Golubev
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Grid-Characteristic Numerical Method on an Irregular Grid with Extending the Interpolation Stencil Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 A. V. Vasyukov, I. E. Smirnov
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Mathematical Model of Human Capital Dynamics Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 N. V. Trusov, A. A. Shananin
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Simulation of Propagation of Dynamic Perturbations in Porous Media by the Grid-Characteristic Method with Explicit Description of Heterogeneities Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 I. A. Mitskovets, N. I. Khokhlov
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Grid Convergence Analysis of Grid-Characteristic Method on Chimera Meshes in Ultrasonic Nondestructive Testing of Railroad Rail Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 A. A. Kozhemyachenko, A. V. Favorskaya
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Dynamics of Chains of Many Oscillators with Unidirectional and Bidirectional Delay Coupling Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 S. A. Kashchenko
Abstract Chains of Van der Pol equations with a large delay in coupling are considered. It is assumed that the number of chain elements is also sufficiently large. In a natural manner, a chain is replaced by a Van der Pol equation with an integral term in the space variable and with periodic boundary conditions. Primary attention is given to the local dynamics of chains with unidirectional and bidirectional
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Modeling Epidemics: Neural Network Based on Data and SIR-Model Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 O. I. Krivorotko, N. Yu. Zyatkov, S. I. Kabanikhin
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Numerical and Analytical Investigation of Shock Wave Processes in Elastoplastic Media Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 L. Wang, I. S. Menshov, A. A. Serezhkin
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Existence of a Solution to Lamb’s Initial-Boundary Value Problem with a Limiting Value of Poisson’s Ratio Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 A. V. Kravtsov
Abstract The paper considers a Lamb’s initial-boundary value problem for an elastic half-space in the case when Poisson’s ratio takes the limiting value of 1/2. The existence of a classical solution in the form of an iterated improper integral in the case of axial symmetry is proved.
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Determining the Spectrum of Eigenvalues and Eigenfunctions for the Bernoulli–Euler Equation with Variable Coefficients by the Peano Method Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 D. D. Zakharov, I. S. Nikitin
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Refined Schemes for Computing the Dynamics of Elastoviscoplastic Media Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 V. I. Golubev, I. S. Nikitin
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Construction of Solutions and Study of Their Closeness in L2 for Two Boundary Value Problems for a Model of Multicomponent Suspension Transport in Coastal Systems Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-16 V. V. Sidoryakina, A. I. Sukhinov
Abstract Three-dimensional models of suspension transport in coastal marine systems are considered. The associated processes have a number of characteristic features, such as high concentrations of suspensions (e.g., when soil is dumped on the bottom), much larger areas of suspension spread than the reservoir depth, complex granulometric (multifractional) content of suspensions, and mutual transitions
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Optimal Control of Quasi-Stationary Equations of Complex Heat Transfer with Reflection and Refraction Conditions Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-01
Abstract The paper considers a class of optimal control problems for a nonlinear parabolic-elliptic system simulating radiative heat transfer with Fresnel matching conditions on surfaces of discontinuity of the refractive index. New estimates for the solution of the initial-boundary value problem are obtained, on the basis of which the solvability of optimal control problems is proved. Non-degenerate
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Lower Bounds for Column Matrix Approximations Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-11-01
Abstract We show a connection between lower and upper bounds on the column matrix approximation accuracy and the bounds on the norms of the pseudoinverses of the submatrices of orthogonal matrices. This connection is exploited to derive lower bounds for column approximations accuracy in spectral and Frobenius norms.
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Gradient-free Federated Learning Methods with l1 and l2-randomization for Non-smooth Convex Stochastic Optimization Problems Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-10-13 B. A. Alashqar, A. V. Gasnikov, D. M. Dvinskikh, A. V. Lobanov
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On the Uniqueness of Solution to Systems of Linear Algebraic Equations to Which the Inverse Problems of Gravimetry and Magnetometry Are Reduced: A Regional Variant Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-10-13 I. I. Kolotov, D. V. Lukyanenko, I. E. Stepanova, A. V. Shchepetilov, A. G. Yagola
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Numerical Method for Estimating the Growth Rate of the Rounding Error in Uniform Metric Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-10-13 M. I. Zuev, S. I. Serdyukova
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Calculation of nth Derivative with Minimum Error Based on Function’s Measurement Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-10-13 A. S. Demidov, A. S. Kochurov
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Constructive Algorithm to Vectorize P ⊗ P Product for Symmetric Matrix P Comput. Math. Math. Phys. (IF 0.7) Pub Date : 2023-10-13 A. I. Glushchenko, K. A. Lastochkin