On Thursday, February 28, 2019 at 12:09:27 PM UTC-7, Brent wrote: > > > > On 2/28/2019 4:07 AM, [email protected] <javascript:> wrote: > > > > On Wednesday, February 27, 2019 at 8:10:16 PM UTC-7, Brent wrote: >> >> >> >> On 2/27/2019 4:58 PM, [email protected] wrote: >> >> *Are you assuming uniqueness to tensors; that only tensors can produce >> covariance in 4-space? Is that established or a mathematical speculation? >> TIA, AG * >> >> >> That's looking at it the wrong way around. Anything that transforms as >> an object in space, must be representable by tensors. The informal >> definition of a tensor is something that transforms like an object, i.e. in >> three space it's something that has a location and an orientation and three >> extensions. Something that doesn't transform as a tensor under coordinate >> system changes is something that depends on the arbitrary choice of >> coordinate system and so cannot be a fundamental physical object. >> >> Brent >> > > 1) Is it correct to say that tensors in E's field equations can be > represented as 4x4 matrices which have different representations depending > on the coordinate system being used, but represent the same object? > > > That's right as far as it goes. Tensors can be of any order. The > curvature tensor is 4x4x4x4. > > 2) In SR we use the LT to transform from one* non-accelerating* frame to > another. In GR, what is the transformation for going from one > *accelerating* frame to another? > > > The Lorentz transform, but only in a local patch. >
*That's what I thought you would say. But how does this advance Einstein's presumed project of finding how the laws of physics are invariant for accelerating frames? How did it morph into a theory of gravity? TIA, AG * > > Brent > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
