Hey guys, I'm having an issue with a question, namely Let x be a subset of S_{4}. Is x a group? x = {e, (123), (132), (12)(34)} I don't really understand how I can test the 4 axioms of a group and how x being a subset of S_{4} would help?
You have only four elements. Why not just write out the entire multiplication table and see if you have a group on your hands?