In this post and the next one, we are going to give all non-equivalent irreducible representations of groups of very small orders. Most of what I’m going to say here has already been discussed in previous posts but now I’m going to put them in one place.

**Example 1**. Irreducible Representations of Finite Abelian Groups: A finite abelian group has exactly non-equivalent irreducible representations. I already gave explicit description of these representations, with an example. See the Question after the theorem in this post.

**Example 2**. Irreducible Representations of : In part 3) in here I showed that has exactly three non-equivalent irreducible representations. One has degree two and the other two have degree one. Note that the dihedral group of order Let be such that For example you may choose and Then every element of is written uniquely as where and

1) Representations of degree one: this for the general case was done in here.

2) Representation of degree two. In here I gave representations of degree two for I showed that all of them are irreducible except those cooresponding to For our case we have So we will have two irreducible representations of degree two. We need one of them only, so I pick the one corresponding to and I call it Let Then, as we saw in there, is defined on by

for all and Thus, explicitly, and

In part (2), We’ll give all non-equivalent irreducible representations of non-abelian groups of order