Showing Levi-Civita properties in 4 dimensions

In summary, the conversation discusses the properties of the Levi-Civita symbol and attempts to prove two equations involving it. The first equation, $$\epsilon_{ijkl}\epsilon_{ijmn}=2!(\delta_{km}\delta_{ln}-\delta_{kn}\delta_{lm}),$$ is shown to be incorrect, leading to a discussion about the possibility of the statement being wrong. The second equation, $$\epsilon_{ijkl}\epsilon_{ijkm}=3!\delta_{lm},$$ is also proven to be incorrect, and the conversation explores various approaches to try and prove it. Ultimately, it is shown that the correct equation is $$\epsilon_{ijkl}\epsilon_{ijkm}=8\delta_{lm}$$ and
  • #1
Phys pilot
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first of all english is not my mother tongue sorry. I want to ask if you can help me with some of the properties of the levi-civita symbol.

I am showing that

$$\epsilon_{ijkl}\epsilon_{ijmn}=2!(\delta_{km}\delta_{ln}-\delta_{kn}\delta_{lm})$$

so i have this...

$$\epsilon_{ijkl}\epsilon_{ijmn}=\delta_{ii}\delta_{jj}\delta_{km}\delta_{ln}+\delta_{ij}\delta_{jm}\delta_{kn}\delta_{li}+\delta_{im}\delta_{jn}\delta_{ki}\delta_{lj}+\delta_{in}\delta_{ji}\delta_{kj}\delta_{lm}-\delta_{ii}\delta_{jn}\delta_{km}\delta_{lj}-\delta_{in}\delta_{jm}\delta_{kj}\delta_{li}-\delta_{im}\delta_{jj}\delta_{ki}\delta_{ln}-\delta_{ij}\delta_{ji}\delta_{kn}\delta_{lm}=3^2\delta_{km}\delta_{ln}+\delta_{kn}\delta_{lm}+\delta_{km}\delta_{ln}+\delta_{kn}\delta_{lm}-3\delta_{km}\delta_{ln}-\delta_{km}\delta_{ln}-3\delta_{km}\delta_{ln}-3\delta_{kn}\delta_{lm}=3\delta_{km}\delta_{ln}-3\delta_{kn}\delta_{lm}=3(\delta_{km}\delta_{ln}-\delta_{kn}\delta_{lm})$$

which is not equal to the supposedly correct answer. can the statement be wrong?
if not i can't see my error.

Also i need to prove that:

$$\epsilon_{ijkl}\epsilon_{ijkm}=3!\delta_{lm}$$
i know and i proved that
$$\epsilon_{ijkl}\epsilon_{ijkl}=24=4!$$
so if $l=m$ i have this
$$\epsilon_{ijkl}\epsilon_{ijkl}=3!\delta_{ll}=3!\cdot 3=18$$
which is not equal to 4!=24 so its the statement wrong again? it must be
$$\epsilon_{ijkl}\epsilon_{ijkm}=8\delta_{lm} $$
Actually i proved that:
$$\epsilon_{ijkl}\epsilon_{ijkm}=\delta_{ii}\delta_{jj}\delta_{kk}\delta_{lm}+\delta_{ij}\delta_{jk}\delta_{km}\delta_{li}+\delta_{ik}\delta_{jm}\delta_{ki}\delta_{lj}+\delta_{im}\delta_{ji}\delta_{kj}\delta_{lk}-\delta_{ii}\delta_{jm}\delta_{kk}\delta_{lj}-\delta_{im}\delta_{jk}\delta_{kj}\delta_{li}-\delta_{ik}\delta_{jj}\delta_{ki}\delta_{lm}-\delta_{ij}\delta_{ji}\delta_{km}\delta_{lk}=3^3\delta_{lm}+\delta_{ik}\delta_{km}\delta_{li}+\delta_{ii}\delta_{lj}\delta_{jm}+\delta_{jm}\delta_{kj}\delta_{lk}-3^2\delta_{lm}-\delta_{jj}\delta_{li}\delta_{im}-3\delta_{ii}\delta_{lm}-\delta_{ii}\delta_{lm}=3^3\delta_{lm}+\delta_{lk}\delta_{km}+\delta_{ii}\delta_{lm}+\delta_{lj}\delta_{jm}-3^2\delta_{lm}-3\delta_{lm}-3^2\delta_{lm}-3\delta_{lm}=3^3\delta_{lm}+\delta_{lm}+3\delta_{lm}+\delta_{lm}-3^2\delta_{lm}-3\delta_{lm}-3^2\delta_{lm}-3\delta_{lm}=8\delta_{lm} $$
Even more if i use my solution:

$$\epsilon_{ijkl}\epsilon_{ijmn}=3(\delta_{km}\delta_{ln}-\delta_{kn}\delta_{lm})$$
to prove
$$\epsilon_{ijkl}\epsilon_{ijkm}=3!\delta_{lm}$$
using $m=k$ and $n=m$ i have this
$$3(\delta_{km}\delta_{ln}-\delta_{kn}\delta_{lm})$$
$$3(\delta_{kk}\delta_{lm}-\delta_{km}\delta_{lk})$$
$$3(3\delta_{lm}-\delta_{lm})$$
$$3(2\delta_{lm})$$
$$6(\delta_{lm})=3!(\delta_{lm})$$
 
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  • #3
Dr Transport said:
Start with the matrix representation using Kronecker deltas then simplify.

https://en.wikipedia.org/wiki/Levi-Civita_symbol#Four_dimensions
That's what i did but when i simplify i get the error and i don't know where i think that the statement is false because i repeat the product too many times and i always get the same
 
  • #4
In 4 dimensions ##\delta_{ii} = 4##.
 
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  • #5
Orodruin said:
In 4 dimensions ##\delta_{ii} = 4##.
that makes sense but if $\delta_{ii}=4$
$$\epsilon_{ijkl}\epsilon_{ijkl}=\delta_{ii}\delta_{jj}\delta_{kk}\delta_{ll}+\delta_{ij}\delta_{jk}\delta_{kl}\delta_{li}+\delta_{ik}\delta_{jl}\delta_{ki}\delta_{lj}+\delta_{il}\delta_{ji}\delta_{kj}\delta_{lk}-\delta_{ii}\delta_{jl}\delta_{kk}\delta_{lj}-\delta_{il}\delta_{jk}\delta_{kj}\delta_{li}-\delta_{ik}\delta_{jj}\delta_{ki}\delta_{ll}-\delta_{ij}\delta_{ji}\delta_{kl}\delta_{lk}=4^4+\delta_{lj}\delta_{jl}+\delta_{ii}\delta_{jj}+\delta_{jl}\delta_{lj}-\delta_{ii}\delta_{jj}\delta_{kk}-\delta_{ii}\delta_{jj}-\delta_{ii}\delta_{jj}\delta_{ll}-\delta_{ii}\delta_{kk}=4^4+\delta_{ll}+4^2+\delta_{jj}-4^3-4^2-4^3-4^2=4^4+4+4^2+4-4^3-4^2-4^3-4^2=120=5!$$

And it should be 4!=24, actually if $\delta_{ii}=3$ it works
$$\epsilon_{ijkl}\epsilon_{ijkl}=\delta_{ii}\delta_{jj}\delta_{kk}\delta_{ll}+\delta_{ij}\delta_{jk}\delta_{kl}\delta_{li}+\delta_{ik}\delta_{jl}\delta_{ki}\delta_{lj}+\delta_{il}\delta_{ji}\delta_{kj}\delta_{lk}-\delta_{ii}\delta_{jl}\delta_{kk}\delta_{lj}-\delta_{il}\delta_{jk}\delta_{kj}\delta_{li}-\delta_{ik}\delta_{jj}\delta_{ki}\delta_{ll}-\delta_{ij}\delta_{ji}\delta_{kl}\delta_{lk}=3^4+\delta_{lj}\delta_{jl}+\delta_{ii}\delta_{jj}+\delta_{jl}\delta_{lj}-\delta_{ii}\delta_{jj}\delta_{kk}-\delta_{ii}\delta_{jj}-\delta_{ii}\delta_{jj}\delta_{ll}-\delta_{ii}\delta_{kk}=3^4+\delta_{ll}+3^2+\delta_{jj}-3^3-3^2-3^3-3^2=3^4+3+3^2+3-3^3-3^2-3^3-3^2=24=4!$$
 
  • #6
You are missing terms. The anti-symmetrisation over the 4 indices should have 4! = 24 terms, not 8.
 
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  • #7
Orodruin said:
You are missing terms. The anti-symmetrisation over the 4 indices should have 4! = 24 terms, not 8.
Yeah, its true, i am sorry.

i am going to do the determinant 4x4
gif&s=2&w=82.&h=76..gif
gif&s=2&w=446.&h=57..gif

and then simplify.
Thanks!
 

1. What are Levi-Civita properties in 4 dimensions?

Levi-Civita properties in 4 dimensions refer to the mathematical properties of a 4-dimensional space that is described by the Levi-Civita symbol. This symbol is used to represent the antisymmetric properties of a 4-dimensional vector space.

2. Why is it important to show Levi-Civita properties in 4 dimensions?

Showing Levi-Civita properties in 4 dimensions is important because it allows us to understand the structure and behavior of 4-dimensional vector spaces, which are widely used in physics and other areas of science. It also helps us to solve mathematical problems involving 4-dimensional spaces.

3. How are Levi-Civita properties in 4 dimensions different from other dimensions?

The Levi-Civita properties in 4 dimensions are different from other dimensions because they are specific to 4-dimensional spaces. In higher dimensions, the Levi-Civita symbol has more components and therefore, more properties. In lower dimensions, the symbol has fewer components and therefore, fewer properties.

4. What are some applications of Levi-Civita properties in 4 dimensions?

Levi-Civita properties in 4 dimensions have various applications in physics, engineering, and other fields of science. They are used to describe the behavior of electromagnetic fields, to model the interactions of particles in quantum mechanics, and to solve problems related to rotations and translations in 4-dimensional spaces.

5. How can we prove the Levi-Civita properties in 4 dimensions?

There are various ways to prove the Levi-Civita properties in 4 dimensions, depending on the specific property to be proven. One approach is to use the definition of the Levi-Civita symbol and apply it to the 4-dimensional vector space. Another approach is to use mathematical techniques such as matrix algebra or differential geometry to show the properties hold in 4 dimensions.

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