cohomology group

例句：

1. 1. Inmathematics, the cohomologygroup of a space is the set ofall homology classes in that space.
   在数学中，一个空间的共形群组是该空间所有同伦类组成的集合。
2. 2. The cohomology group ofa manifold is a topologicalobject that describes how the manifold's boundary behaves under differentiable maps.
   一个流形的共形群是一个拓扑对象，它描述了不同微分映射下流形边界的行为。
3. 3. Incomputer science, the cohomologygroup of a graph is used to studythe connectivity and topological properties of thegraph.
   在计算机科学中，图的共形群用于研究图的连通性和拓扑性质。