Anders Sandberg wrote:
> So the double pairs in some sense correspond to the usual distance
> measures, while the other pairs are more of "mixtures" that occur when
> the coordinate system is not perfectly aligned with the curvature of
> space (locally, you can always set up coordinates to make the tensor
> diagonal, but it doesn't work in general globally).
Ah, ok. Thanks.
>
>
> Now, g is symmetric (that is part of the definition, actually),
> g_ij=g_ji, and in 4-dimensional space that means you can only have 10
> independent components.
>
> However, I'm not entirely certain the 10 components of g explain why
> there are 10 (11) dimensions in string theory, the last paper I read
> about it ("M-theory for laymen" or something similar, available from
> xxx.lanl.gov) just made me more confused.