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- Thread starter Airsteve0
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Bill_K

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ds

which is homogeneous but not isotropic. I'd guess the Weyl tensor for this type of cosmology is nonzero.

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ds^{2}= dt^{2}- a(t)dx^{2}- b(t)dy^{2}- c(t)dz^{2}

which is homogeneous but not isotropic. I'd guess the Weyl tensor for this type of cosmology is nonzero.

Yep, thanks for the correction.

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ds^{2}= dt^{2}- a(t)dx^{2}- b(t)dy^{2}- c(t)dz^{2}

which is homogeneous but not isotropic. I'd guess the Weyl tensor for this type of cosmology is nonzero.

I don't get this. If the expansion rates are anisotropic then it would seem that the space could only be homogeneous at a particular moment in time. From that point becoming inhomogeneous from then on.

???

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Bill_K

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I'm doubtful that a non-isotropic cosmology can be made flat thru a conformal transformation. How do you preserve the angles when going from anisotropy to

ds^{2}= dt^{2}- a(t)dx^{2}- b(t)dy^{2}- c(t)dz^{2}

which is homogeneous but not isotropic. I'd guess the Weyl tensor for this type of cosmology is nonzero.

isotropy?

Editops, I realize this seems to be precisely your point.

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