Cross product for complex vectors

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Discussion Overview

The discussion centers on the definition and geometric interpretation of the cross product for complex vectors, comparing it to the cross product in real vector spaces. Participants explore whether the properties and calculations of the cross product hold in the context of complex vectors.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions if the definition of the cross product is the same for complex vectors and seeks clarification on its geometric interpretation.
  • Another participant asserts that R2 and C are isomorphic, suggesting that the geometric interpretation remains consistent across both spaces, focusing on the norms of the vectors and the cosine of the angle between them.
  • A different participant challenges the assertion about cosine, arguing that the cross product should relate to the sine of the angle instead.
  • There is a mention of the calculation of the cross product using determinants, with a specific example provided for clarity.
  • One participant acknowledges a mix-up between the dot product and the cross product, expressing uncertainty about the definition of the cross product for complex vectors.

Areas of Agreement / Disagreement

Participants express differing views on the geometric interpretation of the cross product, particularly regarding the relationship between the angle and the sine or cosine functions. The discussion remains unresolved regarding the definition and application of the cross product for complex vectors.

Contextual Notes

Some assumptions about the properties of complex vectors and their relationship to real vectors may not be fully articulated. The discussion does not reach a consensus on the definition of the cross product in the context of complex vectors.

dimension10
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I was wondering, is the definition of the cross product the same for complex vectors? And if it is, then how is its geometric interpretation, that is

[tex]||\mathbf{a}\times\mathbf{b}||=||\mathbf{a}|| \; ||\mathbf{b}|| \sin\theta[/tex]

Thanks.
 
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R2 and C are isomorphic.
In particular this means that the geometric interpretation is exactly the same in either R2 or C.
For Rn or Cn, the interpretation is generalized, but it's still the same.
It's still about the norm of the vectors and the cosine of the angle between them.
 
I like Serena said:
R2 and C are isomorphic.
In particular this means that the geometric interpretation is exactly the same in either R2 or C.
For Rn or Cn, the interpretation is generalized, but it's still the same.
It's still about the norm of the vectors and the cosine of the angle between them.

I don't get how it is about the cosine of the angle between them. Shouldn't it be sine?

And is calculating the cross product the same as that for complex vectors? That is,

[tex]\left(a\hat{ \imath}+b\hat{\jmath}+c\hat{k} \right)\times \left( P\hat{\imath}+Q\hat{\jmath}+R\hat{k} \right)=\det\begin{bmatrix}<br /> \hat{\imath} & \hat{\jmath} & \hat{k} \\ <br /> a & b & c \\ <br /> P & Q & R<br /> \end{bmatrix}[/tex]
 
I like Serena said:
R2 and C are isomorphic.
In particular this means that the geometric interpretation is exactly the same in either R2 or C.
For Rn or Cn, the interpretation is generalized, but it's still the same.
It's still about the norm of the vectors and the cosine of the angle between them.
Are you not talking about the dot product? The cross product of two vectors in three dimensions not only has a length but is perpendicular to the two given vectors. In more than three dimensions that is not a single direction.
 
My apologies, that was not one of my brighter responses.
I did indeed mix up the dot product with the cross product.

I'm not aware of any definition of the cross product for complex vectors.
 

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