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In measure theory, the Lebesgue measure, named after French mathematician Henri Lebesgue, is the standard way of assigning a measure to subsets of ''n''-dimensional Euclidean space. For ''n'' = 1, 2, or 3, it coincides with the standard measure of length, area, or volume. In general, it is also called ''n''-dimensional volume, ''n''-volume, or simply volume.〔The term ''volume'' is also used, more strictly, as a synonym of 3-dimensional volume〕 It is used throughout real analysis, in particular to define Lebesgue integration. Sets that can be assigned a Lebesgue measure are called Lebesgue measurable; the measure of the Lebesgue measurable set ''A'' is denoted by λ(''A''). Henri Lebesgue described this measure in the year 1901, followed the next year by his description of the Lebesgue integral. Both were published as part of his dissertation in 1902. The Lebesgue measure is often denoted ''dx'', but this should not be confused with the distinct notion of a volume form. == Definition == Given a subset , with the length of an (open, closed, semi-open) interval given by , the Lebesgue outer measure is defined as :. The Lebesgue measure of E is given by its Lebesgue outer measure if, for every , :. 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「Lebesgue measure」の詳細全文を読む スポンサード リンク
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