Abstract
Abstract We study the asymptotic behaviour of the resolvents $${(\mathcal{A}^\varepsilon+I)^{-1}}$$ ( A ε + I ) - 1 of elliptic second-order differential operators $${{\mathcal{A}}^\varepsilon}$$ A ε in $${\mathbb{R}^d}$$ R d with periodic rapidly oscillating coefficients, as the period $${\varepsilon}$$ ε goes to zero. The class of operators covered by our analysis includes both the “classical” case of uniformly elliptic families (where the ellipticity constant does not depend on $${\varepsilon}$$ ε ) and the “double-porosity” case of coefficients that take contrasting values of order one and of order $${\varepsilon^2}$$ ε 2 in different parts of the period cell. We provide a construction for the leading order term of the “operator asymptotics” of $${(\mathcal{A}^\varepsilon+I)^{-1}}$$ ( A ε + I ) - 1 in the sense of operator-norm convergence and prove order $${O(\varepsilon)}$$ O ( ε ) remainder estimates.
Highlights
The subject of the present article is the investigation of analytical properties of partial differential equations (PDE) of a special kind that emerge in the mathematical theory of homogenisation for periodic composites
In the early 1970’s a number of works appeared concerning the analysis of PDE with periodic rapidly oscillating coefficients, which could be thought of as the simplest, yet already mathematically challenging, object representing the idea of a composite structure
One of the central themes of this activity has been in understanding the relative strength of various notions of convergence in terms of characterising the homogenised medium
Summary
The subject of the present article is the investigation of analytical properties of partial differential equations (PDE) of a special kind that emerge in the mathematical theory of homogenisation for periodic composites. The earlier results [3] concerning resolvent estimates for (1.1)–(1.2) are based on the analysis of spectral projections of the associated operators in a neighbourhood of zero. This approach does not suffice in the double porosity case as all spectral projections provide a leading-order contribution to the behaviour of the resolvent as ε → 0. Bearing this in mind, we analyse the asymptotic behaviour of the operator fibres provided by the Bloch decomposition.
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