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In mathematics, the Kodaira–Spencer map, introduced by Kunihiko Kodaira and Donald C. Spencer, is a map associated to a deformation of a scheme or complex manifold ''X'', taking a tangent space of a point of the deformation space to the first cohomology group of the sheaf of vector fields on ''X''. == Definition == The Kodaira–Spencer map is : where * is a smooth proper map between complex spaces〔The main difference between a complex manifold and a complex space is that the latter is allowed to have a nilpotent.〕 (i.e., a deformation of the special fiber .) * is the connecting homomorphism obtained by taking a long exact cohomology sequence of the surjection whose kernel is the tangent bundle . If is in , then its image is called the Kodaira–Spencer class of ''v''. The basic fact is: there is a natural bijection between isomorphisms classes of and . 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「Kodaira–Spencer map」の詳細全文を読む スポンサード リンク
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