PermutationOrder
PermutationOrder[perm]
gives the order of permutation perm.
Examples
open allclose allApplications (1)
Group elements with order 2 are called involutions. If all elements of a group (except the identity) have order 2, then the group is Abelian (the opposite implication does not hold). This group is Abelian:
The group is Abelian because its multiplication table is symmetric. The involution character of all group elements is expressed by the diagonal of 1s:
Properties & Relations (6)
The order of the identity permutation is defined to be 1:
The order of a permutation can be computed as the least common multiple of the lengths of its cycles:
The order of a permutation equals the order of the cyclic group generated by that permutation:
By Lagrange's theorem, the order of each element of a finite group divides the order of the group. However, not all divisors of the order of a group correspond to the order of some element in the group. Take the alternating group of degree 4, which has order 12, and hence divisors 6, 3, 2:
There is no permutation with order 6:
Cauchy's theorem states that for every prime divisor of the order of a group, there is an element in the group with that order. Take the alternating group of degree 7:
These are the factorization of the order and the orders present:
These are examples of permutations of the 4 prime orders:
Numbers of permutations in with different orders:
Text
Wolfram Research (2010), PermutationOrder, Wolfram Language function, https://reference.wolfram.com/language/ref/PermutationOrder.html.
CMS
Wolfram Language. 2010. "PermutationOrder." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/PermutationOrder.html.
APA
Wolfram Language. (2010). PermutationOrder. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/PermutationOrder.html