In reference [8], some properties such as

Gaussian curvature K(t), Ricci scalar curvature R(t), matter and dark energy density parameters ([[OMEGA].

Then K : M [right arrow] R, K(P) = det S(P) function is called the

Gaussian curvature function of M.

The third edition adds sections on eigenvectors,

Gaussian curvature, and electromagnetism.

where g(x) is the

Gaussian curvature of [partial derivative]X at x, i.

2] or equivalently, there is a nontrivial functional relation [PHI] (K, H) = 0 between its

Gaussian curvature K and mean curvature H.

mu]v] = 0 cannot discriminate about these solutions, additional considerations must be examined: in the following it will be shown that, since R(r) is related to the

Gaussian curvature, it cannot be set equal to the radial coordinate r as in (4) because this brings to unphysical consequences.

2] in (8) is the

Gaussian curvature of a spherical volume of the PV equal to 4[pi][r.

1) is the inverse square root of the

Gaussian curvature of the spherically symmetric geodesic surface in the spatial section [16,17,19].

2] are the PPs'

Gaussian curvature and mass-energy density respectively.

As the curvature force, the mass density, and the

Gaussian curvature are intimately related to the PPs in the negative-energy PV, it is easy to conclude that the Einstein equation and General Relativity must also be intimately related to that vacuum state.

These line-elements, although different, are not disjoint, being coupled by quantities that are determined from the line-element for the interior of the star and by a common

Gaussian curvature at the surface boundary of the object, as the study by Schwarzschild [18] (and my generalisation thereof [5]) for the ideal case of a homogeneous incompressible sphere of fluid teaches us.

It is in fact the radius of curvature, in that it determines the

Gaussian curvature G = 1/[R.