Thread: Proving a set of permutations is a group

Hey there,

I'm trying to prove a set of permutations is a group, but the textbook isn't very clear how to do so.

G={id, (1 2), (1 3), (1 4)}; operation in S_4

If anyone can offer any words of advice, that would be much appreciated.

Originally Posted by manygrams

Hey there,

I'm trying to prove a set of permutations is a group, but the textbook isn't very clear how to do so.

G={id, (1 2), (1 3), (1 4)}; operation in S_4

If anyone can offer any words of advice, that would be much appreciated.

the product of and is . this does not lie in .Hence is not closed under multiplication. How can be a group?