Its propositions hold as well for objects made of rubber as for the rigid figures encountered in metric geometry
它的命题也适用于橡胶制成的物体,也适用于公制几何中遇到的刚性图形。
英语百科
Metric space
In mathematics, a metric space is a set for which distances between all members of the set are defined. Those distances, taken together, are called a metric on the set. A metric on a space induces topological properties like open and closed sets, which lead to the study of more abstract topological spaces.