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In mathematics, a constructible sheaf is a sheaf of abelian groups over some topological space ''X'', such that ''X'' is the union of a finite number of locally closed subsets on each of which the sheaf is a locally constant sheaf. It is a generalization of constructible topology in classical algebraic geometry. In étale cohomology constructible sheaves are defined in a similar way . A sheaf of abelian groups on a Noetherian scheme is called constructible if the scheme has a finite cover by subschemes on which the sheaf is locally constant constructible (meaning represented by an étale cover). The constructible sheaves form an abelian category. The finiteness theorem in étale cohomology states that the higher direct images of a constructible sheaf are constructible. ==References== * 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「constructible sheaf」の詳細全文を読む スポンサード リンク
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