Tensor in D-dimensional space crosswise with 2 vectors

In summary, the person is asking for a tensor that will give him the value of the third vector, F, without having to know the values of the other two vectors. They are not sure if such a tensor exists, but if it does not, they would like to learn more about it.
  • #1
olgerm
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I have 2 vectors ##\vec {V}=(v_1,v_2,v_3,v_4...v_D)## and ##\vec {X}=(x_1,x_2,x_3,x_4...x_D)## in D-dimensional euclidean space.
I want a tensor ,which is crosswise with both of them.

I think that the tensor is parallel with (D-2)-dimensional area, am I right?
I do not know a lot about tensors ,so in answer please also explain me the notation that you used.
 
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  • #2
It's not exactly clear what you want. Do you mean a rank 2 tensor, which we could think of as a matrix? In that case, we can have two possible conditions:

1. ##\sum_j M_{ij} v_j =0##, or
2. ##\sum_j v_j M_{ji}=0##.

You might also want both of these to be satisfied. These conditions are independent unless ##M## is symmetric, ##M_{ij}=M_{ji}##.

Either way, an analog of the Gram-Schmidt process allows you to start with any tensor ##M## and construct a new tensor ##M'## that satisfies one or both of these conditions. For instance, as long as ##|V|\neq 0##,
$$ M'_{ij} = M_{ij} - \sum_k M_{ik} v_k \frac{v_j}{|V|^2}$$
will satisfy ##\sum_j M'_{ij} v_j = 0##. The other combinations should be easy to work out.

Hopefully this component notation is familiar, or at least obvious to you.
 
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  • #3
fzero said:
Do you mean a rank 2 tensor, which we could think of as a matrix?
I can´t explain ,what I mean ,in terms of tensor ,but I´ll try to explain it in terms of what I want it for:
There are 4 vectors ##\vec V_1## ,##\vec V_2## ,##\vec X## and ##\vec F##.
##F⊥V_2##
F is parallel with plane ,which is also parallel with vectors ##\vec X## and ##\vec V_1##

I know only value of vectors ##\vec X## and ##\vec V_1##. My friend knows only value of vector ##\vec V_2##. I want a tensor that I could give to my friend so he could calculate value of ##\vec F## without knowing vectors ##\vec X## and ##\vec V_1## separately.
 
  • #4
Nb: by value I meant the vector itself not length of vector.

I there any such tensor at all ,I wanted? If there is not, it would be useful to learn that there is not.
 

FAQ: Tensor in D-dimensional space crosswise with 2 vectors

What is a tensor?

A tensor is a mathematical object used to represent linear relationships between different sets of variables. It can be thought of as a generalization of a vector and a matrix.

What does "D-dimensional space" refer to?

D-dimensional space refers to a space with D dimensions, where each dimension is represented by a coordinate axis. For example, a 3-dimensional space would have three axes: x, y, and z.

How is a tensor represented in D-dimensional space?

In D-dimensional space, a tensor is represented as an array of numbers with D indices. The number of indices corresponds to the number of dimensions in the space.

What does it mean to "crosswise" a tensor with 2 vectors?

Crosswise refers to the operation of taking the cross product between a tensor and two vectors. This operation results in a new tensor that is orthogonal to both vectors.

What is the significance of using a tensor and 2 vectors together?

Using a tensor and 2 vectors together allows for the representation of complex relationships between multiple variables in D-dimensional space. This can be useful in various scientific fields, such as physics and engineering, for solving problems involving multiple dimensions.

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