An equation with permutations, x^2 = sigma.

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SUMMARY

The discussion revolves around solving the equation x^2 = sigma, where sigma is defined as the permutation (1 2 6 7 5 3 4), a cycle of length seven. Participants concluded that the order of the permutation sigma is 7, leading to the determination that x must equal sigma^4. This conclusion is reached by understanding that since sigma^7 equals the identity permutation, sigma^8 equals sigma, confirming that x can be derived from the properties of the permutation's order.

PREREQUISITES
  • Understanding of permutation cycles and their notation
  • Knowledge of the concept of order of a permutation
  • Familiarity with exponentiation of permutations
  • Basic algebraic manipulation skills
NEXT STEPS
  • Study the properties of permutation groups in abstract algebra
  • Learn about the cycle notation and its applications in combinatorics
  • Explore the concept of the order of a permutation in greater depth
  • Investigate the relationship between permutations and group theory
USEFUL FOR

Mathematics students, particularly those studying abstract algebra, combinatorics, or anyone interested in understanding permutations and their properties.

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Homework Statement



x^2 = sigma.
The permutation sigma = (1 2 6 7 5 3 4), a cycle of length seven.

Determine x!

The Attempt at a Solution



I have tried a few times but my attempts are totally wrong. I don't know where to start! :S

I found a similar problem in the textbook. They could, by just lookin at the problem, say that there is no x for that (in the book not the one above) particular type of permutation. How? :S
 
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I don't know if this is the best way, but it definitely works:
First determine what is the order of sigma. This can be used to solve the question. For example: suppose that the order is 3. Then sigma^3 = 1, so sigma^4 = sigma. From this, you can immediately find x.
If the order would be 4, on the other hand, then you would get sigma^4 = 1 so sigma^5 = sigma. The left hand side is not a square of anything, so there is no solution.
 
I'm not sure if i understood this correct. Let's see, with your reasoning...

I know that sigma^7=1, therefore sigma^8=sigma. Then x=sigma^4. Right?
 
Yes, that's exactly right. I didn't quite comprehend what CompuChip meant by "suppose that the order is 3" since the order was clearly 7! I'm glad you did.
 
I tried not to give away the answer completely. Didn't work :smile:
 

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