Invisible wrote:
> 
> So how *do* you compute the distance between two points in a non-Euclid 
> space anyway?

Generally you start with a notion of something like a dot product 
defined in the tangent spaces of your space and then write out an 
integral to define the arc length of a curve.  Then the distance between 
two points can be defined to be the minimum length of any curve 
connecting them.

> For that matter, is there a way to unambiguously refer to a specific 
> point in such a space?

Depends on the space.  A relatively general but computationally 
cumbersome solution is to cover your space will small Cartesian patches 
which connect together in a "nice" way.  The you can define a point by 
giving its Cartesian patch and its coordinates within that patch.

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