But there is stuff in the universe, so we know it's not Minkowski space.
但是宇宙中是有物质的，所以我们知道宇宙不是明可夫斯基空间。
2
In particular, we give a characteristic of hyperspheres in a Minkowski space.
特别地，我们给出了闵可夫斯基空间中超球面的一个特征。
3
Here, Benedetti considers two types of spacetime with quantum group symmetry - a quantum sphere and k-Minkowski spacetime - and calculates their dimensions.