In the sense of W. Thurston [here](http://en.wikipedia.org/wiki/Geometrization_conjecture#The_eight_Thurston_geometries), there is 3 geometries in dimension 2 and there is 8 geometries in dimension 3. 


Question: **How many different geometries (in the sense of Thurston) do we have in dimension 4 ?**



Thurston geometries in dimension 4
The 4-dimensional geometries were classified in the unpublished thesis of Filipkiewicz, which is available [here](http://wrap.warwick.ac.uk/954/).


