Is this 4-Vector cross product calculation correct?

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Discussion Overview

The discussion centers around the concept of a 4-vector cross product, its validity, and its relation to Maxwell's equations in four-dimensional space-time. Participants explore the mathematical framework and implications of such a construct, including the wedge product and its applications in physics.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant questions the correctness of a proposed 4-vector cross product calculation.
  • Another participant asserts that a 4-vector cross product does not exist, suggesting the wedge product between 1-forms as a more appropriate mathematical tool.
  • A request for clarification on the wedge product and its representation in exterior algebra is made, indicating a lack of understanding of the mathematical concepts involved.
  • One participant suggests that identifying the purpose behind the need for a generalization of the cross product could lead to more appropriate guidance.
  • A participant states their intention to solve Maxwell's equations in four dimensions, indicating the context for their inquiry.
  • Another participant notes that Maxwell's equations are already formulated in four-dimensional space-time and provides the tensor formalism as a reference.
  • A further contribution discusses the application of the cross product in the context of Maxwell's equations, detailing the gradient and its relation to electric and magnetic fields.

Areas of Agreement / Disagreement

Participants express disagreement regarding the existence and validity of a 4-vector cross product. Multiple competing views are presented, particularly concerning the appropriate mathematical framework to use in this context.

Contextual Notes

The discussion reveals limitations in understanding the mathematical structures involved, such as the wedge product and its applications. There are unresolved questions about the definitions and operations related to these concepts.

Who May Find This Useful

This discussion may be useful for individuals interested in advanced mathematical physics, particularly those exploring the relationships between vector calculus, differential forms, and electromagnetic theory in higher dimensions.

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Could someone tell me if this 4-Vector cross product is correct:

i j k t
dx dy dz 1/c*dt
Ex Ey Ez Et
=[(dy(Ez)-dz(Ey))-(dy(Et)-1/c*dt(Ey))+(dz(Et)-1/c*dt(Ez))]*i
-[(d(E)-d(E))-(d(E)-d(E))+(d(E)-d(E))]*j
+[(d(E)-d(E))-(d(E)-d(E))+(d(E)-d(E))]*k
-[(d(E)-d(E))-(d(E)-d(E))+(d(E)-d(E))]*t
 
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There is no such thing as a 4-vector cross product. The closest thing you will get is the wedge product between two 1-forms (or rather, its dual), which is a 2-form.
 
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How do you do the wedge product between 2 1-forms.
I searched for Wedge Product. I got Exterior Algebra. Here are some Equations could someone explain the "^" operator to me.
5bb4798f8855d885779dc1fa14ecfb76826766b9
?
1d43519392c264351c893a0bf4595d21d6860a48
where k=4

3d62b07f8c3aa1d58552a995fa3dd79ed5613cdc
?
 
I believe a better path is to identify your purpose, what do you need a generalisation of the cross product for? Once we have established that, we may be able to point you in an appropriate direction.
 
I am trying to solve Maxwell Equations in 4 dimensions.
 
Maxwell’s equations are already in 4 space-time dimensions. Their appearance in the tensor formalism of special relativity takes the form ##\partial_\mu F^{\mu\nu} = J^\nu## and ##\epsilon^{\mu\nu\sigma\rho}\partial_\nu F_{\sigma\rho}=0##, where F is the antisymmetric rank 2 field tensor.
 
To solve for for some Maxwell Equation it takes the cross product:
grad=dx,dy,dz,1/c*dt
dx = partial d/dx
dy = partial d/dy
dz = partial d/dz
dt = partial d/dt

grad X E(r,t) = -dt(B(r,t))

grad X H(r,t) = dt(D(r,t)) + J
 
Last edited:

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