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In mathematics, specifically commutative algebra, a divided power structure is a way of making expressions of the form meaningful even when it is not possible to actually divide by . == Definition == Let ''A'' be a commutative ring with an ideal ''I''. A divided power structure (or PD-structure, after the French ''puissances divisées'') on ''I'' is a collection of maps for ''n''=0, 1, 2, ... such that: # and for , while for ''n'' > 0. # for . # for . # for , where is an integer. # for , where is an integer. For convenience of notation, is often written as when it is clear what divided power structure is meant. The term ''divided power ideal'' refers to an ideal with a given divided power structure, and ''divided power ring'' refers to a ring with a given ideal with divided power structure. Homomorphisms of divided power algebras are ring homomorphisms that respects the divided power structure on its source and target. 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「Divided power structure」の詳細全文を読む スポンサード リンク
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