Article
Mathematics
Mikihiro Fujii
Summary: In this paper, the compressible Navier-Stokes system around constant equilibrium states is studied. It is proven that there exists a unique global solution for arbitrarily large initial data in the scaling critical Besov space, provided that the Mach number is sufficiently small and the incompressible part of the initial velocity generates the global solution of the incompressible Navier-Stokes equation. Furthermore, the low Mach number limit is considered, and it is shown that the compressible solution converges to the solution of the incompressible Navier-Stokes equation in certain space time norms.
MATHEMATISCHE ANNALEN
(2023)
Article
Mathematics, Applied
Zhihua Huang, Jianfu Yang, Weilin Yu
Summary: This article investigates a free boundary problem that arises in the study of equilibrium for a confined Tokamak plasma in two dimensions. By selecting a suitable flux constant on each connected component of the domain boundary, solutions with multiple sharp peaks near the boundary are constructed and it is proven that the number of solutions to this problem approaches infinity as the parameter tends to infinity.
CALCULUS OF VARIATIONS AND PARTIAL DIFFERENTIAL EQUATIONS
(2023)
Article
Mathematics, Applied
H. Egger, J. Giesselmann
Summary: This article investigates the transportation of gas in long pipes and pipeline networks, where the dynamics are primarily influenced by friction at the pipe walls. By employing nonlinear analysis, the governing equations are formulated as an abstract dissipative Hamiltonian system, enabling us to derive perturbation bounds through relative energy estimates. Consequently, stability estimates with respect to initial conditions and model parameters are proven, and a quantitative asymptotic analysis is conducted in the high friction limit. Initially, the results are established for flow in a single pipe, and then the analysis is extended to pipe networks in the energy-based port-Hamiltonian modeling framework.
NUMERISCHE MATHEMATIK
(2023)
Article
Mathematics
M. A. Kisatov, V. N. Samokhin, G. A. Chechkin
Summary: We generalize the existence and uniqueness theorem for a classical solution to the system of equations describing thermal boundary layers in viscous media with the Ladyzhenskaya rheological law.
DOKLADY MATHEMATICS
(2022)
Article
Nanoscience & Nanotechnology
Giuseppe Cardone, Tiziana Durante
Summary: This article studies a second order elliptic operator in a planar waveguide, where small holes are distributed along a curve and subject to classical boundary conditions on the holes. Under the weak assumptions on the perforation, all possible homogenized problems are described.
NANOSYSTEMS-PHYSICS CHEMISTRY MATHEMATICS
(2022)
Article
Physics, Multidisciplinary
Miloslav Znojil, Denis I. Borisov
Summary: This paper demonstrates the different applications of Arnold's one-dimensional polynomial potentials in classical catastrophe theory and quantum mechanics, particularly within specific dynamical regimes. By relaxing constraints and utilizing perturbative methods, the characteristics of these potentials are investigated.
Article
Mathematics, Applied
Yurij A. Alkhutov, Gregory A. Chechkin, Vladimir G. Maz'ya
Summary: This study considers the variational solution to the Zaremba problem for a divergent linear second-order elliptic equation with measurable coefficients. The problem is set in a local Lipschitz graph domain. An estimate in L2+delta, delta > 0, for the gradient of a solution is proved, and an example of the problem with specific Dirichlet data supported by a fractal set of zero (n-1)-dimensional measure and non-zero p-capacity, p > 1, is constructed.
ARCHIVE FOR RATIONAL MECHANICS AND ANALYSIS
(2022)
Article
Mathematics, Applied
Srinivasan Aiyappan, Giuseppe Cardone, Carmen Perugia, Ravi Prakash
Summary: This paper studies the asymptotic behavior of the solutions of a monotone problem posed in a locally periodic oscillating domain. Nonlinear monotone boundary conditions are imposed on the oscillating part of the boundary, while the Dirichlet condition is considered on the smooth separate part. By using the unfolding method and making natural hypotheses on the regularity of the domain, we prove the weak L-p-convergence of the zero-extended solutions of the nonlinear problem and their flows to the solutions of a limit distributional problem.
NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS
(2022)
Article
Mathematics
D. I. Borisov, P. Exner
Summary: In this paper, a new type of approximation for a second-order elliptic operator with a point interaction in a planar domain is presented. The approximation is of a geometric nature and consists of operators with the same symbol and regular coefficients on the domain with a small hole. The boundary condition is imposed at the boundary of the hole with a coefficient depending on the linear size of the hole. It is shown that as the hole shrinks to a point and the parameter in the boundary condition is scaled appropriately, the approximating family converges in the norm-resolvent sense to the operator with the point interaction. The convergence is established with respect to several operator norms and the convergence rates are estimated.
BULLETIN OF MATHEMATICAL SCIENCES
(2023)
Article
Mathematics, Applied
D. I. Borisov, A. L. Piatnitski, E. A. Zhizhina
Summary: This paper focuses on the spectral properties of a bounded self-adjoint operator in L-2(R-d) that is the sum of a convolution operator with an integrable convolution kernel and an operator of multiplication by a continuous potential converging to zero at infinity. The essential and discrete spectra of this operator are studied. The essential spectrum of the sum is shown to be the union of the essential spectrum of the convolution operator and the image of the potential. Sufficient conditions for the existence of discrete spectrum are provided, and lower and upper bounds for the number of discrete eigenvalues are obtained. The spectral properties of the operators considered in this work are compared with those of classical Schrodinger operators.
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS
(2023)
Article
Mathematics, Applied
G. Cardone, A. Fouetio, S. Talla Lando, J. L. Woukeng
Summary: This work investigates the global dynamics of 2D stochastic tidal equations in a highly heterogeneous environment. Using the stochastic version of the sigma-convergence method and the Prokhorov and Skorokhod compactness theorems, the paper proves that the dynamics at the macroscopic level are of the same type as those at the microscopic level, but with non-oscillating parameters. A corrector-type result is also established.
NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS
(2022)
Article
Mathematics, Applied
D. I. Borisov, J. Kriz
Summary: In this paper, we consider a second order linear elliptic equation in a finely perforated domain. The shapes and distribution of cavities in the domain are arbitrary and non-periodic, and the boundary conditions can be either Dirichlet or nonlinear Robin conditions. We show that under certain conditions, the solution to our problem tends to zero as the perforation becomes finer.
ANALYSIS AND MATHEMATICAL PHYSICS
(2023)
Article
Mathematics, Applied
D. I. Borisov
Summary: In this paper, a boundary value problem for a general second-order linear equation in a perforated domain is considered. The perforation is made by small cavities with a minimal distance between them also being small. Minimal natural geometric conditions are imposed on the shapes of the cavities, while no conditions are imposed on their distribution in the domain. A nonlinear Robin condition is imposed on the boundaries of the cavities. The main results of the paper demonstrate the convergence of the solution of the perturbed problem to that of the homogenized one, providing estimates for the convergence rates in W-2(1)- and L-2-norms uniformly in the L-2-norm of the right-hand side in the equation.
APPLICABLE ANALYSIS
(2023)
Article
Mathematics
Denis Ivanovich Borisov
Summary: We introduce the concept of point interaction for general non-self-adjoint elliptic operators in planar domains. By cutting out a small cavity around the point, we show that these operators can be geometrically approximated. A special Robin-type boundary condition with a nonlocal term is imposed on the boundary of the cavity. As the cavity shrinks to a point, the perturbed operator converges in the norm resolvent sense to a limiting operator with a point interaction containing an arbitrary complex-valued coupling constant. We establish convergence rates for several operator norms. The convergence of the spectrum is proven as a corollary of the norm resolvent convergence.
Article
Mathematics, Applied
S. Aiyappan, Giuseppe Cardone, Carmen Perugia
Summary: In this study, we examine the asymptotic behavior of a linear optimal control problem posed on a locally periodic rapidly oscillating domain. The problem involves an L2-cost functional constrained by a Poisson problem with a mixed boundary condition: a homogeneous Neumann condition on the oscillating part of the boundary and a homogeneous Dirichlet condition on the remaining part.
APPLICABLE ANALYSIS
(2023)
Article
Mathematics
D. I. Borisov
Summary: We study the existence of a limiting operator and the convergence of resolvent norm for a general second order matrix operator subject to a classical boundary condition in a multi-dimensional domain, perturbed by a first order differential operator depending on a small multi-dimensional parameter. Our main results show that the convergence of resolvent norm is equivalent to the convergence of coefficients in the perturbing operator in certain spaces of multipliers. Furthermore, we find that the convergence in these spaces is equivalent to the convergence of local mean values over small pieces of the domain. Our results are supported by examples of non-periodically oscillating perturbations.
JOURNAL OF DIFFERENTIAL EQUATIONS
(2023)
Article
Mathematics
D. I. Borisov, A. L. Piatnitski, E. A. Zhizhina
Summary: This article considers a multiplication operator in L2(R) multiplied by a complex-valued potential, to which a convolution operator multiplied by a small parameter is added. The essential spectrum of such an operator is found in an explicit form, and it is shown that the entire spectrum is located in a thin neighborhood of the spectrum of the multiplication operator.
Correction
Mathematics
M. A. Kisatov, V. N. Samokhin, G. A. Chechkin
DOKLADY MATHEMATICS
(2022)