How does a matrix indicate a point?

  • Context: Undergrad 
  • Thread starter Thread starter mynameinc
  • Start date Start date
  • Tags Tags
    Matrix Point
Click For Summary

Discussion Overview

The discussion revolves around the interpretation of matrices as points in space, specifically in the context of the Birkhoff-von Neumann polytope and permutation matrices. Participants explore how the elements of a matrix correspond to coordinates in different dimensional spaces.

Discussion Character

  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that the vertices of the Birkhoff-von Neumann polytope are represented by permutation matrices, which they claim correspond to points in ℝN2 space.
  • Others clarify that a 2x2 matrix, having four elements, maps to R4, indicating that these matrices represent points in 4-dimensional space.
  • There is a discussion about how to read the elements of a matrix, with some participants suggesting that the entries can be interpreted in a consistent manner to yield coordinates.
  • One participant expresses confusion about how specific matrices translate into points, prompting further explanations from others.

Areas of Agreement / Disagreement

Participants generally agree on the mapping of matrices to points in space, but there is some uncertainty regarding the specific interpretation and representation of these points, particularly in terms of dimensionality and order of entries.

Contextual Notes

There are unresolved aspects regarding the dependence on definitions of dimensionality and the specific context of the Birkhoff-von Neumann polytope. The discussion does not fully clarify how the order of matrix entries affects their interpretation as points.

mynameinc
Messages
9
Reaction score
0
I've been looking at the Birkhoff-von Neumann polytope, and the book stated that the vertices are given by the permutation matrices. So, can someone explain how matrices indicate a point in space?

Thanks,

mynameinc
 
Physics news on Phys.org
The vertices are points in ℝN2 space.
 
D H said:
The vertices are points in ℝN2 space.

I still don't understand. It says that (1 0//0 1), (0 1//1 0) are elements of B_2. How do those indicate points?

If you can't tell, I have several "For Dummies" books. :)
 
Last edited:
A 2x2 matrix has four elements, in this case, four real numbers. That maps to R4, so they are represented by points in 4-space.
 
D H said:
A 2x2 matrix has four elements, in this case, four real numbers. That maps to R4, so they are represented by points in 4-space.

So, does this map as (1,0,1,0) and (0,1,0,1)?

Also, thanks for the help.
 
Usually if you have a matrix you just read it off from left to right, top to bottom. So the matrix

1 0
0 1

would be (1,0,0,1) and the matrix

0 1
1 0

would be (0,1,1,0). Of course it doesn't matter which order you put the entries of your matrix as long as you're consistent the whole time
 
Office_Shredder said:
Usually if you have a matrix you just read it off from left to right, top to bottom. So the matrix

1 0
0 1

would be (1,0,0,1) and the matrix

0 1
1 0

would be (0,1,1,0). Of course it doesn't matter which order you put the entries of your matrix as long as you're consistent the whole time

Those are the coordinates I meant to give, lol.

Thanks for the help DH and Office Shredder. Now that I understand, do I need to place [SOLVED] or anything in the title line?
 

Similar threads

  • · Replies 6 ·
Replies
6
Views
1K
  • · Replies 8 ·
Replies
8
Views
3K
Replies
24
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 14 ·
Replies
14
Views
4K
  • · Replies 11 ·
Replies
11
Views
5K
  • · Replies 7 ·
Replies
7
Views
1K