Inter-universal geometry と ABC予想 (応援スレ) 46at MATHInter-universal geometry と ABC予想 (応援スレ) 46 - 暇つぶし2ch■コピペモード□スレを通常表示□オプションモード□このｽﾚｯﾄﾞのURL■項目テキスト650:現代数学の系譜 雑談 20/05/22 13:50:23.08 koULGAjk.net >>613 つづき ＜障害の理論（英語版）(obstruction theory)＞ https://en.wikipedia.org/wiki/Obstruction_theory Obstruction theory In mathematics, obstruction theory is a name given to two different mathematical theories, both of which yield cohomological invariants. In the original work of Stiefel and Whitney, characteristic classes were defined as obstructions to the existence of certain fields of linear independent vectors. Obstruction theory turns out to be an application of cohomology theory to the problem of constructing a cross-section of a bundle. In homotopy theory The older meaning for obstruction theory in homotopy theory relates to the procedure, inductive with respect to dimension, for extending a continuous mapping defined on a simplicial complex, or CW complex. It is traditionally called Eilenberg obstruction theory, after Samuel Eilenberg. It involves cohomology groups with coefficients in homotopy groups to define obstructions to extensions. (引用終り) 以上 次ページ最新レス表示レスジャンプ類似スレ一覧スレッドの検索話題のニュースおまかせリストオプションしおりを挟むスレッドに書込スレッドの一覧暇つぶし2ch