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In mathematics, more precisely in measure theory, a measure on the real line is called a discrete measure (in respect to the Lebesgue measure) if it is at most concentrated on a countable set. Note that the support need not be a discrete set. Geometrically, a discrete measure (on the real line, with respect to Lebesgue measure) is a collection of point masses. ==Definition and properties== A measure defined on the Lebesgue measurable sets of the real line with values in is said to be discrete if there exists a (possibly finite) sequence of numbers : such that : The simplest example of a discrete measure on the real line is the Dirac delta function One has and More generally, if is a (possibly finite) sequence of real numbers, is a sequence of numbers in of the same length, one can consider the Dirac measures defined by : for any Lebesgue measurable set Then, the measure : is a discrete measure. In fact, one may prove that any discrete measure on the real line has this form for appropriately chosen sequences and 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「Discrete measure」の詳細全文を読む スポンサード リンク
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