On Saturday, March 2, 2019 at 2:29:50 AM UTC-7, [email protected] wrote: > > > > On Friday, March 1, 2019 at 10:14:02 PM UTC-7, [email protected] wrote: >> >> >> >> On Thursday, February 28, 2019 at 12:09:27 PM UTC-7, Brent wrote: >>> >>> >>> >>> On 2/28/2019 4:07 AM, [email protected] 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 * >> > > *Or suppose, using GR, that two frames are NOT within the same local > patch. If we can't use the LT, how can we transform from one frame to the > other? TIA, AG * > > *Or suppose we have two arbitrary accelerating frames, again NOT within > the same local patch, is it true that Maxwell's Equations are covariant > under some transformation, and what is that transformation? TIA, AG* >
*I think I can simplify my issue here, if indeed there is an issue: did Einstein, or anyone, ever prove what I will call the General Principle of Relativity, namely that the laws of physics are invariant for accelerating frames? If the answer is affirmative, is there a transformation equation for Maxwell's Equations which leaves them unchanged for arbitrary accelerating frames? 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.
