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A pseudomanifold is a special type of topological space. It looks like a manifold at most of the points, but may contain singularities. For example, the cone of solutions of forms a pseudomanifold. A pseudomanifold can be regarded as a combinatorial realisation of the general idea of a manifold with singularities. The concepts of orientability, orientation and degree of a mapping make sense for pseudomanifolds and moreover, within the combinatorial approach, pseudomanifolds form the natural domain of definition for these concepts. == Definition == A topological space ''X'' endowed with a triangulation ''K'' is an ''n''-dimensional pseudomanifold if the following conditions hold: # (''pure'') is the union of all ''n''-simplices. # Every is a face of exactly two ''n''-simplices for ''n > 1''. # For every pair of ''n''-simplices σ and σ' in ''K'', there is a sequence of ''n''-simplices such that the intersection is an for all ''i''. 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「pseudomanifold」の詳細全文を読む スポンサード リンク
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