Cycle decomposition of n-cycle's power

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SUMMARY

The discussion focuses on proving that the cycle decomposition of the k-th power of an n-cycle permutation, denoted as a^k, consists of gcd(n, k) cycles, each of size n/gcd(n, k). The key formula utilized is a^k(b_i) = b_{i+k (mod n)}, which illustrates how elements are permuted within the cycle. By examining small examples, participants are encouraged to identify patterns that support this conclusion.

PREREQUISITES
  • Understanding of permutation groups, specifically S_n.
  • Knowledge of cycle notation in permutations.
  • Familiarity with the concept of greatest common divisor (gcd).
  • Basic modular arithmetic principles.
NEXT STEPS
  • Study the properties of permutation groups in detail.
  • Explore the application of gcd in combinatorial problems.
  • Investigate cycle structures in higher-order permutations.
  • Learn about modular arithmetic and its applications in group theory.
USEFUL FOR

Mathematics students, particularly those studying abstract algebra and group theory, as well as educators looking for examples of cycle decomposition in permutations.

TTob
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Homework Statement


let a=(b_1,...,b_n) n-cycle in the permutation group S_n .
prove that the cycle decomposition of a^k consist of gcd(n,k) cycles of n/gcd(n,k) size.

The Attempt at a Solution


I know that [tex]a^k(b_i)=b_{i+k (mod n)}[/tex]
how can it help me ?
 
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Have you tried playing with small examples and looking for patters than you can generalize?
 

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