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In number theory, the Lagarias arithmetic derivative, or number derivative, is a function defined for integers, based on prime factorization, by analogy with the product rule for the derivative of a function that is used in mathematical analysis. Remark: There are many versions of "Arithmetic Derivatives", there are the ones as in this article (Lagarias Arithmetic Derivative), Ihara's Arithmetic Derivative, and Buium's Arithmetic Derivatives. ==Definition== For natural numbers the arithmetic derivative is defined as follows: * for any prime . * for any (Leibniz rule). To coincide with the Leibniz rule is defined to be , as is . Explicitly, assume that : where are distinct primes and are positive integers. Then : The arithmetic derivative also preserves the power rule (for primes): : where is prime and is a positive integer. For example, : The sequence of number derivatives for ''k'' = 0, 1, 2, ... begins : :0, 0, 1, 1, 4, 1, 5, 1, 12, 6, 7, 1, 16, 1, 9, .... E. J. Barbeau was most likely the first person to formalize this definition. He also extended it to all integers by proving that uniquely defines the derivative over the integers. Barbeau also further extended it to rational numbers,showing that the familiar quotient rule gives a well-defined derivative on Q: : Victor Ufnarovski and Bo Åhlander expanded it to certain irrationals. In these extensions, the formula above still applies, but the exponents are allowed to be arbitrary rational numbers. The ''logarithmic derivative'' is a totally additive function. 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「Arithmetic derivative」の詳細全文を読む スポンサード リンク
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