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The meaning of the term "Four-Tensor"



 
 
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  #51  
Old September 27th 03 posted to sci.physics.relativity
WaiteDavid137
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Posts: 574
Default The meaning of the term "Four-Tensor"

Subject: The meaning of the term "Four-Tensor"
From: (Gauge)
Date: 9/26/2003 1:04 PM US Mountain Standard Time
Message-id:

(Gauge) wrote in message
.com...
(WaiteDavid137) wrote in message
...
Subject: The meaning of the term "Four-Tensor"
From:
(Gauge)
Date: 9/25/03 3:59 AM US Mountain Standard Time
Message-id:

Tom Roberts wrote in message
...
On 9/20/2003 8:18 AM, Pmb wrote:
"Randy Poe" wrote in message
om...
Tom Roberts wrote in message

But if one means "element fo the Lorentz group", then there is
indeed a transformation between spherical coordinates in two different
inertial frames;

Since when? Lorentz transformations include boosts, rotations and
relfections.

The Lorentz transformation between two spherical coordinates in this

discussion
IS just a boost.


You're not paying attention again waite. A transformation from a frame
S with Cartesian coordinates to the same frame S with Spherical
coordinates is NOT a Lorentz transformation


Seems I didn't complete that. A transformation which maps
(r,theta,phi) to (r',theta',phi') is not a Lorentz transformation.


You completed your thought and it was wrong. Now you completed a seperate
thought and it is wrong to. The Lorentz transformation between two spherical
coordinate systems is

ct' = gamma[ct - beta*r*cos(theta)sin(phi)]
r'cos(theta')sin(phi') = gamma[rcos(theta)sin(phi) - beta*ct]
r'sin(theta')sin(phi') = rsin(theta)sin(phi)
r'cos(theta') = rcos(theta)

This satisfies the Lorentz group's property of the interval's invariance as it
yields:

dct'^2 - dr'^2 - r'^2[dtheta'^2 + sin^2(theta')dphi'^2] = dct^2 - dr^2 -
r'^2[dtheta^2 + sin^2(theta)dphi^2]

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  #52  
Old September 27th 03 posted to sci.physics.relativity
Gauge
external usenet poster
 
Posts: 1,932
Default The meaning of the term "Four-Tensor"

(WaiteDavid137) wrote in message ...
Subject: The meaning of the term "Four-Tensor"
From:
(Gauge)
Date: 9/26/2003 1:04 PM US Mountain Standard Time
Message-id:

(Gauge) wrote in message
.com...
(WaiteDavid137) wrote in message

...
Subject: The meaning of the term "Four-Tensor"
From:
(Gauge)
Date: 9/25/03 3:59 AM US Mountain Standard Time
Message-id:

Tom Roberts wrote in message
...
On 9/20/2003 8:18 AM, Pmb wrote:
"Randy Poe" wrote in message
om...
Tom Roberts wrote in message

But if one means "element fo the Lorentz group", then there is
indeed a transformation between spherical coordinates in two different
inertial frames;

Since when? Lorentz transformations include boosts, rotations and
relfections.

The Lorentz transformation between two spherical coordinates in this

discussion
IS just a boost.

You're not paying attention again waite. A transformation from a frame
S with Cartesian coordinates to the same frame S with Spherical
coordinates is NOT a Lorentz transformation


Seems I didn't complete that. A transformation which maps
(r,theta,phi) to (r',theta',phi') is not a Lorentz transformation.


You completed your thought and it was wrong.


Bzzzt! Wrong again waite.

Now you completed a seperate
thought and it is wrong to. The Lorentz transformation between two spherical
coordinate systems is

ct' = gamma[ct - beta*r*cos(theta)sin(phi)]
r'cos(theta')sin(phi') = gamma[rcos(theta)sin(phi) - beta*ct]
r'sin(theta')sin(phi') = rsin(theta)sin(phi)
r'cos(theta') = rcos(theta)


Wrong. That is a transformation between S and S' expressed in
Sphercical coordinates. It is NOT a Lorentz transformation.

Whassa matta waite? No speaka de Englaise? You keep making this same
old lame mistake. You START WITH/ASSUME an invalid definition then you
go about stating examples of that invalid definition. Your problem is
that you simply don't know what the "Lorentz Transformation" means.
I've given you resourse after resource from that literature which
DEFINES terms. Thorne's new text is a great resource, especially on
this point. Too bad you refuse to read it or state why you claim
Thorne is wrong

You're becomming more boring than usual waite.

Tell me waite - you've had several days now to contact Thorne. What
was his response to your bogus claims as to why his new text is wrong?
Or are you too ashamed to post his reply?


Mr. Pmb - waite's relativity teacher
  #55  
Old September 27th 03 posted to sci.physics.relativity
WaiteDavid137
external usenet poster
 
Posts: 574
Default The meaning of the term "Four-Tensor"

Subject: The meaning of the term "Four-Tensor"
From: (Gauge)
Date: 9/27/03 7:33 AM US Mountain Standard Time
Message-id:

(WaiteDavid137) wrote in message
...
Subject: The meaning of the term "Four-Tensor"
From:
(Gauge)
Date: 9/26/2003 1:04 PM US Mountain Standard Time
Message-id:

(Gauge) wrote in message
.com...
(WaiteDavid137) wrote in message

...
Subject: The meaning of the term "Four-Tensor"
From:
(Gauge)
Date: 9/25/03 3:59 AM US Mountain Standard Time
Message-id:

Tom Roberts wrote in message
...
On 9/20/2003 8:18 AM, Pmb wrote:
"Randy Poe" wrote in message
om...
Tom Roberts wrote in message

But if one means "element fo the Lorentz group", then there is
indeed a transformation between spherical coordinates in two

different
inertial frames;

Since when? Lorentz transformations include boosts, rotations and
relfections.

The Lorentz transformation between two spherical coordinates in this

discussion
IS just a boost.

You're not paying attention again waite. A transformation from a frame
S with Cartesian coordinates to the same frame S with Spherical
coordinates is NOT a Lorentz transformation

Seems I didn't complete that. A transformation which maps
(r,theta,phi) to (r',theta',phi') is not a Lorentz transformation.


You completed your thought and it was wrong.



Now you completed a seperate
thought and it is wrong to. The Lorentz transformation between two

spherical
coordinate systems is

ct' = gamma[ct - beta*r*cos(theta)sin(phi)]
r'cos(theta')sin(phi') = gamma[rcos(theta)sin(phi) - beta*ct]
r'sin(theta')sin(phi') = rsin(theta)sin(phi)
r'cos(theta') = rcos(theta)


Wrong. That is a transformation between S and S' expressed in
Sphercical coordinates. It is NOT a Lorentz transformation.


I just proved you wrong.

Tell me waite - you've had several days now to contact Thorne. What
was his response to your bogus claims as to why his new text is wrong?


You are a liar as you just now proved to everyone again.

  #57  
Old September 27th 03 posted to sci.physics.relativity
Gauge
external usenet poster
 
Posts: 1,932
Default The meaning of the term "Four-Tensor"

(WaiteDavid137) wrote in message ...
Subject: The meaning of the term "Four-Tensor"
From:
(Gauge)
Date: 9/21/03 5:34 AM US Mountain Standard Time
Message-id:

(WaiteDavid137) wrote in message
...
Subject: The meaning of the term "Four-Tensor"
From: "Pmb"

Date: 9/20/2003 10:14 AM US Mountain Standard Time
Message-id:


then we call the vector
the "position 4-vector."


Position is not a 4-vector. X does not transform as dX


When someone simply says "tensor" it should be the more general definition
according to which the components transform tensorially in the same way as
the differential dX.


Finally got you to change your position I see. About time.


I've said that from day one.


No, You changed your position bewteen the first and second paragraphs quoted
from you in this very post.


Nonsense. I never changed my mind about anything in any post in any
thread with one possible exception - over the years I've stated that I
had no preferance of mass as rest mass or mass as relativistic mass. I
clearly stated several times that I'd reserve my opinion until I've
studied this in every single aspect that I could think of and in which
many others have explained in the peer reviewed literature. At this
time I do not believe that "mass = rest mass" is a valid way to think
of mass.

THAT is the only thing I've changed my mind on.

Mr. Pmb - waite's relativity teacher
  #58  
Old September 28th 03 posted to sci.physics.relativity
Pmb
external usenet poster
 
Posts: 779
Default The meaning of the term "Four-Tensor"


"Tom Roberts" wrote in message
...
Gauge wrote:
Tom Roberts wrote in message

...
Hmmm. This of course depends upon what one means by "Lorentz transform".
If one means the specific equations used in SR then I agree that no such
transform relates spherical coordinates in two different inertial
frames. But if one means "element of the Lorentz group", then there is
indeed a transformation between spherical coordinates in two different
inertial frames;


Since when? Lorentz transformations include boosts, rotations and
relfections. Since when do they include Cartesian to Spherical
transformations?


Please READ WHAT I WROTE.


When you stop being a prick and stop yelling I might just do that - but I
don't see the point in this case since you don't seem to know what a Lorentz
group is.


You are confusing "element of the Lorentz group" with "Lorentz

transformation".

Oh come on now tom. I thought you knew better than this. People expect more
from you than this. *By definition* the "Lorentz Group" is the set of all
Lorentz transformations.

I can't even recall how many times that you've said that a "tensor is
a function on a manifold."


Goodness, I hope I never said that -- it's quite clearly wrong.


I stand (sit actually) corrected. You said that a tensor is a function.

That is indeed a definition of "tensor" (yes, I simplified the
definition and omitted covectors -- IIRC I said so immediately following
the passage you quoted).

A "function on a manifold" is a _FIELD_, not a tensor. But of course
there can be tensor fields (and in GR most of the tensors of interest
are tensor fields).


Are you now changing your mind?


Certainly not. But you need to learn how to read more carefully.


Don't be so condescending roberts. It doesn't become you. Or do you find it
neccesary to act like this?

You REALLY need to learn the difference between "misunderstanding"/"slip"
and needing to "read more carefully" roberts.




Actually a tensor is a function of vectors and 1-forms.


That's what the passage of mine you quoted said. You REALLY need to
learn how to read more carefully.


I saw no mention of one-forms. YOU? need to (1) pay more attention and (2)
stop acting like davy waite.

I tend to stop reading your posts when I see start being a prick.


And yet, in my earlier discussion the direction of my arm is a vector
(aka a rank-1 tensor), but it's sure not obvious how it is a
function.... If tensors are to be defined as functions of rank-1
tensors, that recursive definition must "bottom out" somewhere, and
vectors is where that happens.


Why? Vectors and 1-forms are not defined in terms of tensors. Not from what
I've seen.

Just READ WHAT I WROTE


and this is where you were well into being a prick.


Pmb


  #59  
Old September 30th 03 posted to sci.physics.relativity
Gauge
external usenet poster
 
Posts: 1,932
Default The meaning of the term "Four-Tensor"

(WaiteDavid137) wrote [****]

That parrot is still here? Go away scooter and come back when you grow up

Mr. Pmb - waite's relativity teacher
 




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