Cyclic Permutations: εijk, Even or Odd?

In summary, a cyclic permutation is a rearrangement of elements in a set or sequence in which the first element becomes the last, the second becomes the first, and so on. The notation "εijk" represents the Levi-Civita symbol, which determines the parity of a permutation. The symbol is defined as 1 for an even permutation, -1 for an odd permutation, and 0 for any two indices being the same. It can only be used for 3-element permutations, and is commonly used in science to describe rotations and in mathematical calculations.
  • #1
Karol
1,380
22
εijk is the permutation symbol and cyclic permutations, for example 123→231→312, are always even, thus ε123231312=+1, but:
ε132213321=-1
I understand the first 2, but ε321 is even, no? and also all this series is cyclic, it's not all even and...
 
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  • #2
Why would ##\varepsilon_{321}## be even?
 
  • #3
micromass said:
Why would ##\varepsilon_{321}## be even?
Oh sorry, right, but my original question is why is it written in a textbook that every cyclic permutation is even while the cyclic permutations ε132=ε213=ε321 are odd?
 

FAQ: Cyclic Permutations: εijk, Even or Odd?

What is a cyclic permutation?

A cyclic permutation is a rearrangement of the elements in a set or sequence in which the first element becomes the last, the second becomes the first, and so on. This means that the elements are shifted in a circular pattern.

What does the notation "εijk" mean in cyclic permutations?

The notation "εijk" represents the Levi-Civita symbol, which is used to denote the parity (even or odd) of a permutation. It is defined as 1 if the indices ijk are an even permutation of 123, -1 if they are an odd permutation, and 0 if any two indices are the same.

How is the parity of a cyclic permutation determined using "εijk"?

The parity of a cyclic permutation can be determined by counting the number of times the elements are shifted in a circular pattern. If the number of shifts is even, the permutation is even and the Levi-Civita symbol will be 1. If the number of shifts is odd, the permutation is odd and the symbol will be -1.

Can "εijk" be used for any size of cyclic permutation?

No, the Levi-Civita symbol "εijk" can only be used for a 3-element cyclic permutation. For larger permutations, different notations and methods must be used to determine the parity.

How are cyclic permutations used in science?

Cyclic permutations are used in many areas of science, including mathematics, physics, and chemistry. They are often used to describe the rotation of objects or particles, as well as in mathematical proofs and calculations involving permutations and combinations.

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