As mathematicians say, “Every simply connected closed 3-manifold is homeomorphic to a 3-sphere.”

用数学语言表达就是“每个单连通3重（3-manifold）封闭体与一个三维球体同胚（homeomorphic）。”

youdao

Also, the paper discuss the existence of the infinite closed geodesics of a compact no-simply connected Riemannian manifold.

并由此讨论了紧致的非单连通黎曼流形上无穷多的闭测地线存在性问题。

youdao

Algorithm of DNA computing for time-table problem was obtained with introducing manifold biochemical experiments on closed circle DNA computing model.

基于闭环dna计算模型引入多种生化实验得出求解排课表问题的DNA算法。

youdao