Category Archives: 3-manifold
Let us prove:
Let be a short exact sequence, if the center then
Proof: When then , so .
that is, a curve ,…
Strangely, there are very few places that offer simple types or simple constructions of these topological beings. Sometimes innocent guessing make us to think that only is the only space we need to appreciate all the available 3d-complexity.
Today there are: “obvious ones”
To learn more, follow to the elementary classes of 3-manifolds lists.