Describing vectors in n dimensions

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Discussion Overview

The discussion revolves around the representation of vectors in n-dimensional space, exploring how vectors can be expressed in terms of their components across various dimensions. Participants discuss notation, the relationship between components and basis vectors, and the implications of representing vectors in higher dimensions.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that a vector A can be expressed as A = A_x + A_y + A_z + ... + A_n, indicating that additional components can be added for higher dimensions.
  • Others clarify that the representation of vectors must consider the basis, suggesting a more formal notation such as V = V^{\alpha}e_{\alpha}, which implies summation over indices.
  • There is a discussion about the notation used, with some participants expressing confusion over symbols like the ellipsis and the square symbol.
  • One participant mentions their book's notation for vectors, which includes unit vectors, and attempts to reconcile it with the notation discussed in the thread.
  • Some participants express uncertainty about the notation and concepts introduced by others, indicating varying levels of familiarity with the subject matter.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best way to represent vectors in n dimensions, with multiple competing views on notation and the role of basis vectors remaining evident throughout the discussion.

Contextual Notes

Some participants express uncertainty regarding specific notations and concepts, highlighting a potential limitation in their understanding of vector representation in higher dimensions.

Nano-Passion
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Recall that A can be broken up into its components x,y, and z. Can You simply add more components to describe any number of dimensions. Where n would be nth dimension?

A=A_x+ A_y+A_z+⋯A_n
 
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What's the square symbol for? And why do you have theoretical physics degree in your status thingy? Do you mean you will someday hope to get such a degree? I'm hoping of doing a theoretical phd someday. I didn't know there was such a thing as a purely theoretical undergraduate degree, if that's what youre talking about?

About the question: If we have a vector A, then it can be written (in some basis) as its components (A1,A2,A3,A4) For a four-dimensional vector, so yeah, there are as many components as there are dimensions.
 
BruceW said:
What's the square symbol for? And why do you have theoretical physics degree in your status thingy? Do you mean you will someday hope to get such a degree? I'm hoping of doing a theoretical phd someday. I didn't know there was such a thing as a purely theoretical undergraduate degree, if that's what youre talking about?

About the question: If we have a vector A, then it can be written (in some basis) as its components (A1,A2,A3,A4) For a four-dimensional vector, so yeah, there are as many components as there are dimensions.

For PhD I wrote what I'm striving for. Perhaps that isn't what I should do. :devil: I'll edit it.

I've only begun my third semester. :)

Edit: What square symbol?
 
Last edited:
A=A_x+ A_y+A_z+⋯A_n
The symbol ⋯ just before A_n it looks like two horizontal lines..
 
BruceW said:
A=A_x+ A_y+A_z+⋯A_n
The symbol ⋯ just before A_n it looks like two horizontal lines..

Oh sorry, that is supposed to be an ellipse (...) that indicates the sequence.
 
You don't write it that way. The components are relative to a basis as Bruce mentioned. A vector can be represented as a linear combination of components relative to said basis vectors so it would be written compactly as V = V^{\alpha }\vec{e}_{\alpha } where the repeated indices imply summation over all possible values the index can take. So, for example, a vector V \in \mathbb{R}^{n} can be written, when equipped with the Cartesian chart, as V = V^{x}\vec{e_{x}} + ... + V^{n}\vec{e_{n}} where \vec{e_{x}} = (1, 0, ..., 0) and similarly for the other basis vectors.
 
WannabeNewton said:
You don't write it that way. The components are relative to a basis as Bruce mentioned. A vector can be represented as a linear combination of components relative to said basis vectors so it would be written compactly as V = V^{\alpha }\vec{e}_{\alpha } where the repeated indices imply summation over all possible values the index can take. So, for example, a vector V \in \mathbb{R}^{n} can be written, when equipped with the Cartesian chart, as V = V^{x}\vec{e_{x}} + ... + V^{n}\vec{e_{n}} where \vec{e_{x}} = (1, 0, ..., 0) and similarly for the other basis vectors.

I have to admit, I am not familiar with that notation. But I will mention that my book stated A=A_x\widehat{i}+A_y\widehat{j}+A_z\widehat{k}. Which is why I simply put:

A=A_x\widehat{i}+A_y\widehat{j}+A_z\widehat{k}+...A_n\widehat{t}
 
Last edited:
Nano-Passion said:
I have to admit, I am not familiar with that notation. But I will mention that my book stated A=A_x\widehat{i}+A_y\widehat{j}+A_z\widehat{k}. Which is why I simply put:

A=A_x\widehat{i}+A_y\widehat{j}+A_z\widehat{k}+...A_n\widehat{t}

No that is perfectly correct. It just wasn't in your original post is all.
 

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