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In algebraic topology, a discipline within mathematics, the acyclic models theorem can be used to show that two homology theories are isomorphic. The theorem was developed by topologists Samuel Eilenberg and Saunders MacLane. They discovered that, when topologists were writing proofs to establish equivalence of various homology theories, there were numerous similarities in the processes. Eilenberg and MacLane then discovered the theorem to generalize this process. It can be used to prove the Eilenberg–Zilber theorem. ==Statement of the theorem== Let be an arbitrary category and be the category of chain complexes of -modules. Let be covariant functors such that: * for . * There are for such that has a basis in , so is a free functor. * is - and -acyclic at these models, which means that for all and all . Then the following assertions hold: * Every natural transformation is induced by a natural chain map . * If are natural transformations, are natural chain maps as before and for all models , then there is a natural chain homotopy between and . * In particular the chain map is unique up to natural chain homotopy.〔 〕 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「Acyclic model」の詳細全文を読む スポンサード リンク
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