Prove in Sn: The set of all the even permutations is a subgroup of Sn.
(Sn = S sub n)
Thanks for any help!...
Do you understand what is being asked here? $\displaystyle S_n$ is the set of all permutations on n objects. You only need to prove that the set of even permutations is closed under the group operation of composition. Is the composition of two even permutations even? What is the definition of even permutation?