Contents

Mathematical Notes


Vol. 120, No. 1-2, 2026


Research Articles

Generalized Dense Chains

V. I. Varankina and E. M. Vechtomov p. 3  abstract

Solvability Conditions for Convolution Type Integral Equations

G. A. Grigorian p. 8  abstract

Constructive Gibbs Measures for the Three-State Ising–Potts Model on a Cayley Tree

B. M. Isakov and M. M. Rahmatullaev p. 17  abstract

On Constructible Sets in Simpson’s Set Theory

V. G. Kanovei and V. A. Lyubetsky p. 27  abstract

On Some Generalizations of \(E\)-Groups

O. A. Karpov, E. A. Timoshenko, A. G. Tisovskii, and A. V. Tsarev p. 41  abstract

On the Fixed Point Theorems of Meir–Keeler Type and Applications on Fréchet Algebras

Kieu Phuong Chi, Pham Hoang Quan, and Do Hoai Vu p. 55  abstract

On the Frattini Subgroup and the \(p\mathfrak{F}\)-Hypercenter of a Finite Group

Zhengtian Qiu, Zixi Ni, and Shouhong Qiao p. 70  abstract

On the Behavior of the Shannon Function for the Depth of Boolean Functions in the Standard Basis

S. A. Lozhkin and M. D. Sergeev p. 77  abstract

Double Factorization Systems in an Equivariant Topology

E. V. Mart’yanov p. 83  abstract

On Some Property of a Simplex Inscribed in a Ball

M. V. Nevskii p. 105  abstract

On Boundary Layer Solutions in the Reaction–Diffusion Problem with a Singularly Perturbed Nonlinear Boundary Condition of Integral Type

E. I. Nikulin p. 111  abstract

Intuitionistic Epistemic Logic from the Point of View of Classical Logic

A. A. Onoprienko p. 132  abstract

Correlation Length Lower Bound for the Random-Field Potts Model with the Greedy Lattice Animal

P. Rigas p. 150  abstract

Degenerate Resonance in Systems with Damped Oscillatory Perturbations

O. A. Sultanov p. 157  abstract

Partial Sums of the Reciprocal Gaussian \(Q\)-Binomial Coefficients

Wenchang Chu and Emrah Kılıç p. 170  abstract

Solvability of Neumann–Dirichlet Inverse Problem for Stieltjes String with Mixed Spectral Data

Lu Zhou, Yongxia Guo, Yuanyuan Liu, and Guangsheng Wei p. 178  abstract


Short Communications

Parity of Extremal Functions of Embedding of Sobolev Spaces on an Interval with Uniform Norm and Dirichlet Boundary Conditions

D. D. Kazimirov p. 196  abstract

Bilinear Addition Theorems and Somos Sequences

F. E. Pelevin p. 200  abstract


Research Articles

Generalized Abel Integral Operator on an Interval with Constant Coefficients and Nonlinear Equations

S. N. Askhabov p. 207  abstract

Nonharmonic Fourier Series and Sharp Bernstein Type Inequalities

O. L. Vinogradov p. 216  abstract

Comparison Theorems for a Fourth-Order Variational Equation on a Metric Graph

S. A. Gotsoev and R. Ch. Kulaev p. 231  abstract

A Short Note on \(\rho\)-Semipermutable Subgroups of Finite Groups

Shuo Guo, Haoran Yu, and Xiaowei Xu p. 242  abstract

Mechanics-Like Singularly Perturbed Optimal Control Problems

A. R. Danilin and O. O. Kovrizhnykh p. 246  abstract

A Note on Absolutely Minimal Extensions in Finite Metric Spaces

A. Domínguez Corella and T. M. Lê p. 262  abstract

Inverse Problem for the Inhomogeneous One-Dimensional Euler–Poisson–Darboux Equation with Variable Potential

D. K. Durdiev and T. R. Suyarov p. 270  abstract

On a Distribution of Edges of Higher-Dimensional Klein Polyhedra

A. A. Illarionov p. 281  abstract

An Interchange Lemma for Categorial Dependency Grammars

B. N. Karlov p. 292  abstract

On the Monotonicity of Sequences Related to the Dirichlet and Lagrange Spectra

M. S. Lavrov p. 306  abstract

Averaging Abstract Hyperbolic Equations

V. B. Levenshtam and M. R. Yavaeva p. 320  abstract

A Source Identification Problem for a Class of Subdiffusion Equations Involving Nonlinear Intensity

Nguyen Thi Van Anh, Tran Dinh Ke, and Bui Thi Hai Yen p. 327  abstract

Analysis of Normalized Solution to an Elliptic Free Boundary Value Problem Driven by a Critical Nonlinearity

S. Sahu, D. Choudhuri, and L. Mbarki p. 346  abstract

Homogeneous Polynomials Defined on Spaces of Measurable Vector Functions

V. A. Tamaeva p. 358  abstract

On an Inequality for Critical Values of \(k\)-Symmetric Polynomials

D. M. Khammatova p. 366  abstract

Integration of the Nonlinear Complex Modified Korteweg–de Vries (CMKdV) Equation with a Self-Consistent Source in the Form of a Series

T. G. Khasanov p. 372  abstract

Robust Stability of High-Order Delay Systems with Unknown Parameters

Guang-Da Hu p. 386  abstract


Short Communications

Ergodic Support of a Dynamical System and a Natural Representation of Choquet Distributions for Invariant Measures

V. I. Bakhtin p. 392  abstract

On Bloch Eigenfunctions of Sarnak Operator

D. I. Borisov and A. A. Fedotov p. 396  abstract