Publication date: 2025-07-01 07:16:00 Authors: I. Ullah; R. Magdalena Category:
Environmental Sciences
Summary: The study investigates the nexus between innovation, labor migrations, energy consumption and CO2
emissions in Germany
for the period 1990–2020. This study applied a dynamic simulated ARDL (DS-ARDL) model for estimation, which can
observe the negative and positive variations in variables both in long run and short run. The dependent variable in DS-ARD
provides a more intuitive picture of dynamic effects than coefficients alone. In Addition, DS-ARDL may provide reliable
estimations even if sample size is smaller. The results of this study suggest a long-term relationship among innovation,
migration, energy consumption, and CO2 emissions. The results also confirm that migration has a positive relationship with
CO2
emissions, while innovation has an adverse effect on CO2 emissions in long run. Policymakers can take action on both
ends of the supply and demand spectrum to lessen the impact of migration on Germany's CO2
emissions. Human capital
accumulation provided by international migration; therefore, receiving countries should encourage rapid technological
advancement and improve their citizens' spending habits.
Author keywords: Migration; Energy consumption; Innovation; CO2 emissions; Germany
Publication date: 2025-06-10 11:08:00 Authors: E. Mamedov; Y. Sezer; A.R. Safarova Category:
Mathematics
Summary: In this paper we consider the Dirichlet problem for the Laplace equation
in Hardy classes generated by an additive-invariant Banach function space on the unit
circle. It is shown that the classical Dirichlet problem for the Laplace equation has a
unique solution for every boundary function from the considered space. It is considered
a boundary problem for the Laplace equation with oblique derivatives in the Hardy
classes generated by separable subspaces of rearrangement-invariant spaces in which the
infinitely differentiable functions are dense. Noetherness of this problem is established
and the index of this problem is calculated.
Author keywords: Banach function space; additive-invariant; Laplace equation; oblique derivatives; Noetherness; Hardy class
Publication date: 2025-06-10 11:06:00 Authors: E. H. Sow; O. Sall Category:
Mathematics
Summary: We determine the set of algebraic points of degree degree l ≥ 2 over Q on
the curve X given by the affine equation n2 = 3(m5 −1) and this result extends a result
of Siksek who described in [5] the set of algebraic points of degree 1 on this curve.
Summary: Let G be a locally compact hypergroup and let K be a compact subhypergroup
such that (G,K) is a Gelfand pair. Let μ be a bounded complex-valued Borel measure on G , and let T♮μ be the corresponding convolution operator of L1♮(G), the subset of L1(G) consisting of K-bi-invariant functions. Suppose that S is a bounded linear
operator on a Banach space X. We prove that every linear operator Ψ : X −→ L1♮(G)
such that ΨS = T♮ μΨ is continuous if and only if (S, T ♮ μ) has no critical eigenvalues.
Publication date: 2025-06-10 08:07:00 Authors: Tohirjon A. Abduvahobov; Tursun K. Yuldashev Category:
Mathematics
Summary: In this article the questions of existence and uniqueness of (ω, c)−periodic
solution of boundary value problem for an impulsive system of ordinary differential equations
with product of two nonlinear functions and mixed maxima are studied. This problem
is reduced to the investigation of solvability of the system of nonlinear functionalintegral
equations. The method of contracted mapping is used in the proof of unique
solvability of nonlinear functional-integral equations in the space BD([0, ω],Rn). Obtained
an estimate for the (ω, c)−periodic solution of the studying problem.
Author keywords: Impulsive system of differential equations; product of two nonlinear functions; (ω, c)−periodic solution; mixed maxima; contracted mapping; existence and uniqueness.
Summary: This paper investigates an age-structured optimal harvest control model from both theoretical and
numerical perspectives. First, we apply classical optimal control techniques to establish the existence of an optimal
control, derive the necessary conditions, conduct a steady-state analysis, and characterize the bang-bang regime.
Subsequently, we numerically solve of the problem using an appropriate discretization method to support the
theoretical results.
Summary: This work presents a novel and comprehensive approach to the study of
Bertrand curves in 4-dimensional Minkowski space (R41
). We introduce a new Frenet
frame specifically tailored for analyzing Bertrand curves in the (1, 3)-normal plane, which
allows us to derive significant relationships between the curvature functions κ1, κ2, and
κ3. Our analysis provides new formulas and explicit conditions for these curvatures,
offering a deeper understanding of their geometric properties in R41
.
We investigate four distinct cases of Bertrand curves, each characterized by specific
conditions on the curvature functions. For each case, we derive explicit solutions and
relationships, demonstrating the versatility of our approach. Furthermore, we establish
the existence of a Bertrand mate curve ζ∗ for a given Bertrand curve ζ and derive the
parameter λ that defines the mate curve. This parameter is expressed in terms of the
curvature functions, providing a clear connection between the original curve and its mate.
To illustrate the practical application of our theoretical results, we provide detailed examples
of Bertrand curve pairs in R41
. These examples include the explicit construction of
the Frenet frames and the computation of the associated curvature functions, showcasing
the effectiveness of our methodology.
Author keywords: Bertrand curves; new Frenet frame; curvature functions; Minkowski space
Publication date: 2025-06-10 07:59:00 Authors: Misir J. Mardanov; Telman K. Melikov; Gulnar V. Hajiyeva Category:
Mathematics
Summary: This article explores minimum of an extremal in the variational problem with
delay under the degeneracy of the Weierstrass condition. Here for study the minimality
of extremal, variations of the Weierstrass type are used in two forms: in the form of
variations on the right with respect to the given point, and in the form of variations
on the left with respect to the same point. Further, using these variations, formulas for
the increments of the functional are obtained. The exploring of the minimality of the
extremal with the help of these formulas is conducted under the assumption that the
Weierstrass condition degenerates. As a result, considering different forms of degenerations
(degeneracy of the Weieristrass condition at a single point and at points of a certain
interval), we obtain the necessary conditions of the inequality type and the equality type
for a strong and weak local minimum. A specific example is given to demonstrate the
effectiveness of the results obtained in this article.
Author keywords: variational problem with delayed argument; strong (weak) local minimum; necessary condition type equality (inequality); degeneration at the point.
Summary: We explicitly determine the algebraic point families of a given degree over Q
of the curve C1,2(7) with affine equation:
y7 = x(x − 1)2
This curve is a special case of the family of quotients of Fermat curves Cr,s(p) described
in [11] of affine equation:
yp = xr(x − 1)s with 1 ≤ r, s, r + s ≤ p;
for r = 1, s = 2 and p = 7 such a curve was considered in [10]. This curve has been
studied by O. Sall in [14], where the author gives a parametrisation of the cubic points. It
should be noted, however, that the method used by O. Sall does not allow us to determine
the set of points of degree greater than 3. We have therefore used a geometric method
to extend this work and determine the quartic points [4]. In this note, we describe all
the families of algebraic points of given degree, geometrically specifying the contact lines
and the curve containing them, by applying the fundamental Abel-Jacobi theorem [1, 9],
before using these results with a Q-basis of the linear systems L(m∞) and combining the
contact order of the curve and specific points to obtain analytical expressions for these
families of points.
Publication date: 2025-06-10 07:56:00 Authors: M. Bayramoglu; I. Jabbarov; A. Zeynalov; M. Ismailova Category:
Mathematics
Summary: In the present work, we consider the metric questions of diffeomorphic mappings
of the manifolds. We find such bases on tangential spaces of manifolds corresponding
to given mappings, which allow investigate their metric properties, independent of
connection coefficients, by using of strictly analysis’ methods. For simplicity of our considerations,
we suffice with consideration of manifolds defined by finite number of maps.
When our consideration is restricted with neighborhoods of some points, we shall suffice
with one map defining the manifold.