1. Stability of a Solution to One Combined Mixed Problem for the Klein–Gordon–Fock Equation with a Variable Coefficient

   • M. F. Abdukarimov

   OriginalPaper 23 July 2021 Pages: 45 - 52

2. An Example of Noncomputability of Exponents of a System of Ordinary Differential Equations

   • A. V. Tyulenev

   OriginalPaper 23 July 2021 Pages: 53 - 59

3. Local Modeling of Liouville Foliations by Billiards: Implementation of Edge Invariants

   • V. V. Vedyushkina

   OriginalPaper 23 July 2021 Pages: 60 - 64

   

4. Influence of the Choice of the Class of Gauge Functions on the Properties of the Henstock–Kurzweil Integral

   • S. N. Kopylov

   OriginalPaper 23 July 2021 Pages: 65 - 68

5. Plane Sets That are Chebyshev in Some Norm

   • K. S. Shklyaev

   OriginalPaper 23 July 2021 Pages: 69 - 72

6. Frames as Continuous Redundant Codes

   • Al. R. Valiullin
   • Ar. R. Valiullin
   • V. V. Galatenko

   OriginalPaper 23 July 2021 Pages: 73 - 77

7. An Example of Complete but Not Global Perron Instability

   • A. A. Bondarev

   OriginalPaper 23 July 2021 Pages: 78 - 82

8. Theory of Families of Polytopes: Fullerenes and Pogorelov Polytopes

   • N. Yu. Erokhovets

   OriginalPaper 23 July 2021 Pages: 83 - 95