sci.physics.relativity

On Feb 28, 8:03 pm, Edward Green wrote:
> On Feb 26, 1:45 am, Koobee Wublee wrote:

> > For example, I have the following simple matrix with elements a, b, c,
> > and d. As you have already agreed that a, b, c, and d can be observer
> > dependent.
>
> I have? Oh... I suppose you mean that a,b,c,d are the components of a
> tensor.

Yes.

> > [a, b]
> > [c, d]
>
> > Now, if I factor out any non-zero element (say a), the above matrix
> > becomes the following.
>
> > a [1, b / a]
> > [c / a, d / a]
>
> > If the original matrix as you have claimed can be observer
> > independent,
>
> I did? You just said that I agreed that the components were "observer
> dependent". Perhaps that's what you meant.

Yes.

> > then how can you justify the second matrix with elements
> > 1, (b / a), (c / a), and (d / a) to be observer dependent since the
> > factor a is observer dependent as well?
>
> By "observer dependent" we mean "coordinate system dependent" or
> "basis dependent". If I factor out a non-zero number then implicitly
> I'm changing the units. The numeric values of the elements of a
> tensor are dependent on the choice of units as well as on the
> orientation of the basis vectors.
>
> So where is the problem?

The problem is that you are still stuck in your matheMagic realm where
you can turn an ordinary matrix into a tensor by saying
'abracadabra'.

> > You need to resolve this mathematical conflict of yours in order for
> > us to continue our discussions.
>
> That's OK. I'll leave it be.

Thank you.

> I recall your handle from a few years ago, at which time I formed some
> spot model something like "grad student posting under a funny name,
> semi-serious". I see that at least now I must at least revise my
> estimation of either your skill or your intent: you either know and
> understand even less than even I do, which is not a very high upper
> bound, and are arrogant about it, or your intent is to laugh at the
> stupidity of people who try to reason with you, or you are
> impersonating the original holder of that handle on gmail, or any
> combination of these conditions.

What handle is that? Do you know me?

> > The rest of crap is snipped mercifully.
>
> Thanks for the kind words.

You are very welcome.

> Likewise, I'm sure.

Where?