morning
I think I left off with a discussion of tensors and their multidimensionality (Thus they are straight lines and not straight lines depending upon the POV of the observer).
Tensors are what Einstein used to warp space time from flat to curved.
The sauce on this tensor subject is kinda weak.
Why? It should not be weak - it is still simple geometry - but this is where data appears missing or weak and the researched areas basically just say - you won't understand.
Tensors are connected to topology.