Thread: Klein 4-group

Let H be the Klein 4-group. To which familiar group is the quotient group
S4/H isomorphic? Justify your answer.

Any suggestions or hints would be fabulous!

My only suggestion would be to sit down and do it! , the group of permutations on 4 "symbols", contains 4!= 24 elements. It is tedious but not impossible to write out its operation table. It has a subgroup isomorphic to the Klein group (if it didn't this problem would make no sense). Can you identify that subgroup? has 8 members. Can you work out the operation table for it from the operation table for ?

Originally Posted by HallsofIvy

My only suggestion would be to sit down and do it! , the group of permutations on 4 "symbols", contains 4!= 24 elements. It is tedious but not impossible to write out its operation table. It has a subgroup isomorphic to the Klein group (if it didn't this problem would make no sense). Can you identify that subgroup? has 8 members. Can you work out the operation table for it from the operation table for ?

A little typo slip there: has 6 elements, of course, and since there are only two different groups,

up to isomorphism, of order 6, there are no many options from where to choose...

Now, remember that a quotient group is abelian iff the normal subgroup contains the derived, or commutator, subgroup

of the whole group, which is here , so...

Tonio

Oops, yes, 24/4= 6, not 8! I really need to work on my arithmetic!