- #1
TGlad
- 136
- 1
Hi,
Wikipedia lists about 10 vacuum solutions of the Einstein Field Equations.
However, if I look for topologies of Einstein space, there are many different families, which include Calabi-Yau manifolds, of which abelian, Enriques, Hyperelliptic and K3 surfaces are subsets. Within K3 surfaces alone there are computed lists of 15,000 families (https://projecteuclid.org/euclid.em/1175789798).
So I am wondering how there can be so many known topologies which allow Ricci-flat metrics, but so few known Ricci-flat metrics (vacuum solutions).
I imagine that many topologies don't have analytic "exact" metric formulae, but then I wonder how they can know a topology can admit a Ricci-flat metric if they have no examples of such metrics.
Wikipedia lists about 10 vacuum solutions of the Einstein Field Equations.
However, if I look for topologies of Einstein space, there are many different families, which include Calabi-Yau manifolds, of which abelian, Enriques, Hyperelliptic and K3 surfaces are subsets. Within K3 surfaces alone there are computed lists of 15,000 families (https://projecteuclid.org/euclid.em/1175789798).
So I am wondering how there can be so many known topologies which allow Ricci-flat metrics, but so few known Ricci-flat metrics (vacuum solutions).
I imagine that many topologies don't have analytic "exact" metric formulae, but then I wonder how they can know a topology can admit a Ricci-flat metric if they have no examples of such metrics.