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In commutative algebra, the Auslander–Buchsbaum formula, introduced by , states that if ''R'' is a commutative Noetherian local ring and ''M'' is a non-zero finitely generated ''R''-module of finite projective dimension, then : Here pd stands for the projective dimension of a module, and depth for the depth of a module. ==Applications== The Auslander–Buchsbaum formula implies that a Noetherian local ring is regular if, and only if, it has finite global dimension. In turn this implies that the localization of a regular local ring is regular. If ''A'' is a local finitely generated ''R''-algebra (over a regular local ring ''R''), then the Auslander–Buchsbaum formula implies that ''A'' is Cohen–Macaulay if, and only if, pd''R''''A'' = codim''R''''A''. 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「Auslander–Buchsbaum formula」の詳細全文を読む スポンサード リンク
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