Lukshin, A. V. Reznik, B. I.
Published in
Computational Mathematics and Modeling

We consider the inverse problem of source identification for the heat conduction problem. The neoclassical formulation of the direct problem with integral boundary condition is used. Conditions for unique solvability of the inverse problem are obtained.

Makeev, V. V.
Published in
Journal of Mathematical Sciences

Here are three samples of results. (1) Let m be a finite (absolutely) continuous mass distribution in ℝ2, and let ℓ = {ℓ1, ..., ℓ5 ⊂ ℝ2} be a quintuple of rays with common origin such that any two adjacent angles between them make a sum of at most π. Then an affine image of ℓ subdivides m into five parts with any prescribed ratios. (2) For each fin...

Permiakova, E.
Published in
Lithuanian Mathematical Journal

In this paper, we prove a criterion of convergence in distribution in the Skorokhod space. We apply this criterion to some special Levy processes and obtain almost-sure versions of limit theorems for these processes.

Kátai, I.
Published in
Lithuanian Mathematical Journal

We characterize the q-multiplicative functions which belong to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$\mathcal{L}^\alpha $$ \end{document} or \documentclass[1...

Zalgaller, V. A.
Published in
Journal of Mathematical Sciences

It is proved that a regular tetrahedron has the maximal possible surface area among all tetrahedra having surface with unit geodesic diameter. An independent proof of O’Rourke-Schevon’s theorem about polar points on a convex polyhedron is given. A. D. Aleksandrov’s general problem on the area of a convex surface with fixed geodesic diameter is disc...

Tripol’skii, A. I. Strizhak, P. E.
Published in
Theoretical and Experimental Chemistry

An approach based on the interrelationship between the activation energy of the rate-limiting step of a heterogeneous catalytic reaction and the structure of the catalyst surface expressed in terms of fractal geometry is presented for the example of the oxidation of carbon monoxide. The activation energy of this reaction was shown to increase with ...

Krivchenkov, I. V.
Published in
Theoretical and Mathematical Physics

We derive the eikonal equation for an electromagnetic wave propagating in an external electromagnetic field according to the laws of nonlinear electrodynamics. Based on Logunov’s geometrization principle, we determine the metric tensors of the effective Riemannian spaces for the Born-Infeld electrodynamics, nonlinear Heisenberg-Euler electrodynamic...

Gupta, Ch. K. Romanovskii, N. S.
Published in
Algebra and Logic

Let B be a class of groups A which are soluble, equationally Noetherian, and have a central series A = A1 ⩾ A2 ⩾ … An ⩾ … such that ⋂An = 1 and all factors An/An+1 are torsion-free groups; D is a direct product of finitely many cyclic groups of infinite or prime orders. We prove that the wreath product D ≀ A is an equationally Noetherian group. As ...

Mutlutürk, M.
Published in
Journal of Mining Science

The lack of a proper decision variable impedes the planning of dimensional stone quarry operation. So far, “quasi-grade”, which may measure the stone quality, developed via multivariate statistical methods is offered as decision variable. However, the marketable blocks of dimensional stones should satisfy not only stone quality requirements, but al...

Voronov, B. L. Gitman, D. M. Tyutin, I. V.
Published in
Theoretical and Mathematical Physics

We consider the quantum mechanical problem of a relativistic Dirac particle moving in the Coulomb field of a point charge Ze. It is often declared in the literature that a quantum mechanical description of such a system does not exist for charge values exceeding the so-called critical charge with Z = α−1 = 137 because the standard expression for th...