section_path: In topology
section_name: In topology
paragraph_text: In topology
  
  Three-dimensional space has a number of topological properties that distinguish it from spaces of other dimension numbers. For example, at least three dimensions are required to tie a knot in a piece of string.
  
  In differential geometry the generic three-dimensional spaces are 3-manifolds, which locally resemble R 3 {\displaystyle {\mathbb {R} }^{3}}.