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In mathematics, more particularly in functional analysis, differential topology, and geometric measure theory, a k-current in the sense of Georges de Rham is a functional on the space of compactly supported differential k-forms, on a smooth manifold ''M''. Formally currents behave like Schwartz distributions on a space of differential forms. In a geometric setting, they can represent integration over a submanifold, generalizing the Dirac delta function, or more generally even directional derivatives of delta functions (multipoles) spread out along subsets of ''M''. ==Definition== Let denote the space of smooth ''m''-forms with compact support on a smooth manifold . A current is a linear functional on which is continuous in the sense of distributions. Thus a linear functional : is an ''m''-current if it is continuous in the following sense: If a sequence of smooth forms, all supported in the same compact set, is such that all derivatives of all their coefficients tend uniformly to 0 when tends to infinity, then tends to 0. The space of ''m''-dimensional currents on is a real vector space with operations defined by : Much of the theory of distributions carries over to currents with minimal adjustments. For example, one may define the support of a current as the complement of the biggest open set such that : whenever The linear subspace of consisting of currents with support (in the sense above) that is a compact subset of is denoted . 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Current (mathematics)」の詳細全文を読む スポンサード リンク
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