Vol 88, No 4 (2024)
Articles
On subspaces of Orlicz spaces, generated by independent copies of a mean zero function
Abstract
Linear isometric invariants of bounded domains
Abstract
Codimensions of identities of solvable Lie superalgebras
Abstract
The Dirichlet problem for the inhomogeneous mixed type equation with the Lavrentiev-Bitsadze operator
Abstract
Homogenization of elliptic and parabolic equations with periodic coefficients in a bounded domain under the Neumann condition
Abstract
Let $\mathcal{O}\subset\mathbb{R}^d$ be a bounded domain of class $C^{1,1}$. In $L_2(\mathcal{O};\mathbb{C}^n)$, we consider a selfadjoint second-order matrix elliptic differential operator $B_{N,\varepsilon}$, $0<\varepsilon\leqslant1$, under the Neumann boundary condition. The principal part of this operator is given in a factorized form. The operator includes first-order and zero-order terms. The coefficients of the operator $B_{N,\varepsilon}$ are periodic and depend on $\mathbf{x}/\varepsilon$. We study the generalized resolvent $(B_{N,\varepsilon}-\zeta Q_0(\cdot/\varepsilon))^{-1}$, where $Q_0$ is a periodic bounded and positive definite matrix-valued function, and $\zeta$ is a complex parameter. We obtain approximations of the generalized resolvent in the operator norm in $L_2(\mathcal{O};\mathbb{C}^n)$ and in the norm of operators acting from $L_2(\mathcal{O};\mathbb{C}^n)$ to the Sobolev class $H^1(\mathcal{O};\mathbb{C}^n)$, with two-parametric (with respect to $\varepsilon$ and $\zeta$) error estimates. The results are applied to study the behavior of solutions of the initial boundary value problem with the Neumann condition for the parabolic equation $Q_0(\mathbf{x} / \varepsilon) \partial_t \mathbf{u}_\varepsilon(\mathbf{x},t) = -( B_{N,\varepsilon} \mathbf{u}_\varepsilon)(\mathbf{x},t)$ in the cylinder $\mathcal{O} \times (0,T)$, where $0 < T\leqslant\infty$