Contents

Russian Mathematics

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Vol. 70, No. 3, 2026

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Weighted Inequalities for the Differences of Averages over Lacunary Sequences on L^p Spaces

Sakin Demir p. 1  abstract

Initial-Boundary Value Problem for an Inhomogeneous Heat Equation with Piecewise Constant Delay

D. K. Durdiev, S. H. Xolikov, and H. H. Turdiev p. 10  abstract

Local Boundary Value Problem for One Class of Third-Order Equations of Elliptic-Hyperbolic Type

B. I. Islomov, B. Z. Usmonov, and A. A. Abdullaev p. 20  abstract

Legendrian Submanifolds

E. S. Kornev p. 30  abstract

On the Reduction of a Second-Order Differential System to a Realization with a Polylinear Controller Invariant with Respect to Independently Controllable Trajectory Bundles

A. V. Lakeyev, Yu. È. Linke, and V. A. Rusanov p. 41  abstract

Generalized Wavelet Packet Associated with Bessel Function

K. Moungkang, C. P. Pandey, and S. K. Singh p. 57  abstract

Refined Nonlinear Deformation Models of Cylindrical Shape for Fiber-Reinforced Composite Plates: 2. A Model of Third-Order Accuracy

V. N. Paimushin, M. V. Makarov, N. V. Levshonkova, and M. A. Shishov p. 67  abstract

Simultaneous Mean-Squared Approximations of Periodic Functions and the Widths of Classes of Functions in the Space L₂

G. A. Yusupov and M. A. Mavlonazarov p. 81  abstract

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