A Physics forum. Physics Banter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » Physics Banter forum » Physics Newsgroups » Physics - General (alternative forum)
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Tags:

tensors



 
 
Thread Tools Display Modes
  #1  
Old June 23rd 05 posted to alt.sci.physics
Aesop
external usenet poster
 
Posts: 8
Default tensors

Rambling


If i take a cube and unfold it in a way that it becomes a planar object then
there is degeneracy in terms of dimension - The planar form for 3D is a
Cross Crucifix) - the forth dimension of time added results in a 3D cross
(This is not the only configuration) the form is a translation of the
original shape.


Question?

What symbol *should* represent 11 dimensions?

Kieran


Ads
  #2  
Old June 23rd 05 posted to alt.sci.physics
Anthony Smales
external usenet poster
 
Posts: 43
Default tensors


"Aesop" wrote in message
...
Rambling


If i take a cube and unfold it in a way that it becomes a planar object
then
there is degeneracy in terms of dimension - The planar form for 3D is a
Cross Crucifix) - the forth dimension of time added results in a 3D cross
(This is not the only configuration) the form is a translation of the
original shape.


Question?

What symbol *should* represent 11 dimensions?

Kieran


This is an object known as a 'tesseract' - unfolding results in an object
one dimension lower, so it is a trick we can use to visualise higher
dimensions. It is not possible to visualise an 11 dimensional one, but you
can express it mathematically (via topology). There is some good information
on this in the book 'Hyperspace' by Michio Kaku

p.s. Salvador Dali featured the 3D tesseract you mention in his crucifiction
painting


  #3  
Old June 23rd 05 posted to alt.sci.physics
tadchem
external usenet poster
 
Posts: 1,987
Default tensors



Aesop wrote:
Rambling


It shows...

If i take a cube and unfold it in a way that it becomes a planar object


Wrong. A cube is a 3-D object. It cannot be "unfolded" into a 2-D
object. You are probably thinking about the *surface* of a cube.

There are many topologically distinct ways that 6 squares can be
arranged so that they can be folded up into the surface of a cube.

then
there is degeneracy in terms of dimension - The planar form for 3D is a
Cross Crucifix)


I don't know which definition of the word 'degeneracy' you are using
here,
http://www.onelook.com/?w=degeneracy&ls=a
but in the mathematical sense
http://mathworld.wolfram.com/Degenerate.html
it does not apply to this situation.

- the forth


"fourth"?

dimension of time added results in a 3D cross


I infer you are referring to the shape depicted he
http://en.wikipedia.org/wiki/Tesseract
And where is the 'time' dimension of your 3-D cross? What does it add
to the figure that was absent before it was added?

(This is not the only configuration) the form is a translation of the
original shape.


"translation?" In which direction or into what language? Again your
misuse of the words leads to miscommunication.

Question?

What symbol *should* represent 11 dimensions?


The usual mathematical convention is a special font capital Roman R
followed by a superscript representing the number of dimensions (in
your case, "11"):
http://mathworld.wolfram.com/Dimension.html

Tom Davidson
Richmond, VA

  #4  
Old June 23rd 05 posted to alt.sci.physics
tadchem
external usenet poster
 
Posts: 1,987
Default tensors

http://en.wikipedia.org/wiki/Tesseract
http://mathworld.wolfram.com/Tesseract.html
http://mathworld.wolfram.com/Hypercube.html

Tom Davidson
Richmond, VA

  #5  
Old June 23rd 05 posted to alt.sci.physics
Aesop
external usenet poster
 
Posts: 8
Default tensors


"tadchem" wrote in message
oups.com...


Aesop wrote:
Rambling


It shows...

If i take a cube and unfold it in a way that it becomes a planar object


Wrong. A cube is a 3-D object. It cannot be "unfolded" into a 2-D
object. You are probably thinking about the *surface* of a cube.

There are many topologically distinct ways that 6 squares can be
arranged so that they can be folded up into the surface of a cube.

then
there is degeneracy in terms of dimension - The planar form for 3D is a
Cross Crucifix)


I don't know which definition of the word 'degeneracy' you are using
here,
http://www.onelook.com/?w=degeneracy&ls=a
but in the mathematical sense
http://mathworld.wolfram.com/Degenerate.html
it does not apply to this situation.

- the forth


"fourth"?

dimension of time added results in a 3D cross


I infer you are referring to the shape depicted he
http://en.wikipedia.org/wiki/Tesseract
And where is the 'time' dimension of your 3-D cross? What does it add
to the figure that was absent before it was added?

(This is not the only configuration) the form is a translation of the
original shape.


"translation?" In which direction or into what language? Again your
misuse of the words leads to miscommunication.

Question?

What symbol *should* represent 11 dimensions?


The usual mathematical convention is a special font capital Roman R
followed by a superscript representing the number of dimensions (in
your case, "11"):
http://mathworld.wolfram.com/Dimension.html

Tom Davidson
Richmond, VA


Tom drop your red pen for a moment please and consider

Degenerate

Having declined or or deteriorated to a lower physical level (2D
representation of a 3D object)

Translation

Any form that changes to another is 'translated' (Rather than the strict
matematical sense)

I am assuming, perhaps incorrectly, you have the intellect to think in
english as well as mathematics

I was thinking about the surface of the cube (granted - hangs head in shame)

I am familiar with the R term - What I was thinking about was unfolding the
3D cross as I did the Cube and adding another dimension to the resulting 2D
object making it a 5D representation of the original object (using the same
scheme as with the cube - cross)

My question was what would be the resulting shape for 11 dimensions

Kieran





  #6  
Old June 23rd 05 posted to alt.sci.physics
Aesop
external usenet poster
 
Posts: 8
Default tensors


"Anthony Smales" wrote in message
...

"Aesop" wrote in message
...
Rambling


If i take a cube and unfold it in a way that it becomes a planar object
then
there is degeneracy in terms of dimension - The planar form for 3D is a
Cross Crucifix) - the forth dimension of time added results in a 3D

cross
(This is not the only configuration) the form is a translation of the
original shape.


Question?

What symbol *should* represent 11 dimensions?

Kieran


This is an object known as a 'tesseract' - unfolding results in an object
one dimension lower, so it is a trick we can use to visualise higher
dimensions. It is not possible to visualise an 11 dimensional one, but you
can express it mathematically (via topology). There is some good

information
on this in the book 'Hyperspace' by Michio Kaku

p.s. Salvador Dali featured the 3D tesseract you mention in his

crucifiction
painting


Man nailed to a 4 dimensional existence?





  #7  
Old June 23rd 05 posted to alt.sci.physics
tadchem
external usenet poster
 
Posts: 1,987
Default tensors



Aesop wrote:

snip

Degenerate

Having declined or or deteriorated to a lower physical level (2D
representation of a 3D object)

Translation

Any form that changes to another is 'translated' (Rather than the strict
matematical sense)

I am assuming, perhaps incorrectly, you have the intellect to think in
english as well as mathematics


I am educated in the contextual definitions of words in both fields -
my mother was a proofreader for newspapers and my father was a
physicist, my first undergraduate degree was in mathematics (I am now a
chemist). You yourself established the context as mathematics, and I
would have been presumptive to assume you were changing contexts in
mid-discussion. Now that I have your admission, I can adapt. My wife
does it to me all the time - but then she's just an engineer.

I am familiar with the R term - What I was thinking about was unfolding the
3D cross as I did the Cube and adding another dimension to the resulting 2D
object making it a 5D representation of the original object (using the same
scheme as with the cube - cross)

My question was what would be the resulting shape for 11 dimensions


There are 11 distict *nets* for the 3-D cube (that is what your 'cross'
shape obtained from unfolding the surface of cube onto a 2-D surface is
called):
http://mathworld.wolfram.com/Cube.html
http://mathworld.wolfram.com/Net.html

The tesseract (4-dimensional cube) has 261 "nets"
http://mathworld.wolfram.com/Tesseract.html

The number of nets grows rapidly with the order of the hypercube. The
Online Encyclopedia of Integer Sequences
http://www.research.att.com/cgi-bin/...i?Anum=A091159
does not give the number of nets for hypercubes beyond the tesseract,
although they are calculable - not that I know how off the top of my
head.

The page
http://mathworld.wolfram.com/Hypercube.html
displays 2-dimensional projections of the hypercubes of orders
(dimensionality) 2 through 7.

Extrapolating from a study of these we can see the following:

The 11-D hypercube will have 2^11 (2048) vertices (corners), with 11
edges meeting at each vertex from orthogonal (perpendicular) directions
(total 11,264 edges), each edge shared by 10 square faces (total 28,160
square faces), and it gets complicated after that...

HTH

Tom Davidson
Richmond, VA

  #8  
Old June 23rd 05 posted to alt.sci.physics
Anthony Smales
external usenet poster
 
Posts: 43
Default tensors


"Aesop" wrote in message
...

"Anthony Smales" wrote in message
...

"Aesop" wrote in message
...
Rambling


If i take a cube and unfold it in a way that it becomes a planar object
then
there is degeneracy in terms of dimension - The planar form for 3D is a
Cross Crucifix) - the forth dimension of time added results in a 3D

cross
(This is not the only configuration) the form is a translation of the
original shape.


Question?

What symbol *should* represent 11 dimensions?

Kieran


This is an object known as a 'tesseract' - unfolding results in an object
one dimension lower, so it is a trick we can use to visualise higher
dimensions. It is not possible to visualise an 11 dimensional one, but
you
can express it mathematically (via topology). There is some good

information
on this in the book 'Hyperspace' by Michio Kaku

p.s. Salvador Dali featured the 3D tesseract you mention in his

crucifiction
painting


Man nailed to a 4 dimensional existence?


I think its called 'Christus Hypercubus'
here it is: http://mapage.noos.fr/dardelf2/museum5/Dali-corpus.jpg




  #9  
Old June 23rd 05 posted to alt.sci.physics
Anthony Smales
external usenet poster
 
Posts: 43
Default tensors


"tadchem" wrote in message
oups.com...


Aesop wrote:

snip

Degenerate

Having declined or or deteriorated to a lower physical level (2D
representation of a 3D object)

Translation

Any form that changes to another is 'translated' (Rather than the strict
matematical sense)

I am assuming, perhaps incorrectly, you have the intellect to think in
english as well as mathematics


I am educated in the contextual definitions of words in both fields -
my mother was a proofreader for newspapers and my father was a
physicist, my first undergraduate degree was in mathematics (I am now a
chemist). You yourself established the context as mathematics, and I
would have been presumptive to assume you were changing contexts in
mid-discussion. Now that I have your admission, I can adapt. My wife
does it to me all the time - but then she's just an engineer.

I am familiar with the R term - What I was thinking about was unfolding
the
3D cross as I did the Cube and adding another dimension to the resulting
2D
object making it a 5D representation of the original object (using the
same
scheme as with the cube - cross)

My question was what would be the resulting shape for 11 dimensions


There are 11 distict *nets* for the 3-D cube (that is what your 'cross'
shape obtained from unfolding the surface of cube onto a 2-D surface is
called):
http://mathworld.wolfram.com/Cube.html
http://mathworld.wolfram.com/Net.html

The tesseract (4-dimensional cube) has 261 "nets"
http://mathworld.wolfram.com/Tesseract.html

The number of nets grows rapidly with the order of the hypercube. The
Online Encyclopedia of Integer Sequences
http://www.research.att.com/cgi-bin/...i?Anum=A091159
does not give the number of nets for hypercubes beyond the tesseract,
although they are calculable - not that I know how off the top of my
head.

The page
http://mathworld.wolfram.com/Hypercube.html
displays 2-dimensional projections of the hypercubes of orders
(dimensionality) 2 through 7.

Extrapolating from a study of these we can see the following:

The 11-D hypercube will have 2^11 (2048) vertices (corners), with 11
edges meeting at each vertex from orthogonal (perpendicular) directions
(total 11,264 edges), each edge shared by 10 square faces (total 28,160
square faces), and it gets complicated after that...

HTH

Tom Davidson
Richmond, VA


So the Euler number, X would be :
X = V - E + F
X = 2048 - 11264 + 28160 = 18944 (Euler numbers of equivalent surfaces are
equal)


  #10  
Old June 24th 05 posted to alt.sci.physics
Aesop
external usenet poster
 
Posts: 8
Default tensors


"tadchem" wrote in message
oups.com...


Aesop wrote:

snip

Degenerate

Having declined or or deteriorated to a lower physical level (2D
representation of a 3D object)

Translation

Any form that changes to another is 'translated' (Rather than the strict
matematical sense)

I am assuming, perhaps incorrectly, you have the intellect to think in
english as well as mathematics


I am educated in the contextual definitions of words in both fields -
my mother was a proofreader for newspapers and my father was a
physicist,



Being of - is no guarantee of being

my first undergraduate degree was in mathematics (I am now a
chemist). You yourself established the context as mathematics,


No it was rambling

and I
would have been presumptive to assume you were changing contexts in
mid-discussion. Now that I have your admission, I can adapt. My wife
does it to me all the time - but then



she's just an engineer. (private joke no doubt)



I am familiar with the R term - What I was thinking about was unfolding

the
3D cross as I did the Cube and adding another dimension to the resulting

2D
object making it a 5D representation of the original object (using the

same
scheme as with the cube - cross)

My question was what would be the resulting shape for 11 dimensions


There are 11 distict *nets* for the 3-D cube (that is what your 'cross'
shape obtained from unfolding the surface of cube onto a 2-D surface is
called):
http://mathworld.wolfram.com/Cube.html
http://mathworld.wolfram.com/Net.html

The tesseract (4-dimensional cube) has 261 "nets"
http://mathworld.wolfram.com/Tesseract.html

The number of nets grows rapidly with the order of the hypercube. The
Online Encyclopedia of Integer Sequences

http://www.research.att.com/cgi-bin/...es/eisA.cgi?An
um=A091159
does not give the number of nets for hypercubes beyond the tesseract,
although they are calculable - not that I know how off the top of my
head.

The page
http://mathworld.wolfram.com/Hypercube.html
displays 2-dimensional projections of the hypercubes of orders
(dimensionality) 2 through 7.

Extrapolating from a study of these we can see the following:

The 11-D hypercube will have 2^11 (2048) vertices (corners), with 11
edges meeting at each vertex from orthogonal (perpendicular) directions
(total 11,264 edges), each edge shared by 10 square faces (total 28,160
square faces), and it gets complicated after that...

HTH


Whats HTH?

Tom Davidson
Richmond, VA


Kieran


 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Help with tensors Schoenfeld Physics - General Discussion 16 August 29th 05 10:01 AM
Help with tensors Schoenfeld The Theory of Relativity 16 August 29th 05 10:01 AM
Tensors Anthony Smales The Theory of Relativity 13 December 21st 04 04:41 AM
Why two different tensors? Starblade Darksquall Current Physics Research (Moderated) 40 September 30th 03 07:50 AM
Tensors. Starblade Darksquall Physics - General Discussion 17 September 10th 03 08:23 AM


All times are GMT +1. The time now is 06:01 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.Search Engine Friendly URLs by vBSEO 2.4.0
Copyright ©2004-2008 Physics Banter, part of the NewsgroupBanter project.
The comments are property of their posters.
Masters Degrees Online - Loans - Myspace Layouts - Loans - Credit Card