closed manifold

例句：

1. 1. The closed manifold is a mathematical concept that describes the properties of a three-dimensional shape with no gaps or holes.
   封闭的多面体是一个数学概念，它描述了三维形状的属性，没有缝隙或洞。
2. 2. In geometry, a closed manifold is a region in space that has no boundary linesand is therefore infinite in all directions.
   在几何学中，封闭的多面体是在空间中没有边界线的区域，因此在所有方向上都是无限的。
3. 3.The closed manifold theory has applications in various fields such as topology, physics, and computer science.
   封闭的多面体理论在各个领域都有应用，如拓扑学、物理学和计算机科学。