B4.2
Part II, 2003
Assume that the group of matrices of determinant 1 with entries from the field has presentation
Show that the subgroup generated by is central and that the quotient group can be identified with the alternating group . Assuming further that has seven conjugacy classes find the character table.
Is it true that every irreducible character is induced up from the character of a 1-dimensional representation of some subgroup?
[Hint: You may find it useful to note that may be regarded as a subgroup of , providing a faithful 2-dimensional representation; the subgroup generated by and is the quaternion group of order 8 , acting irreducibly.]