# Math Help - Help about rep group!

1. ## Help about rep group!

Let G be an nonabelian has oder of 8. Let x be a character. Show that x(1)=1

2. Originally Posted by thanhuthe
Let G be an nonabelian has oder of 8. Let x be a character. Show that x(1)=1

A character is always a group homomorphism, so...

Tonio

Ps. By the way, the above is true for ANY group, not only non-abelian ones of order 8.

3. Do you mean a multiplicative character (linear character) or a character of a representation? If you are referring the latter, it is not always true that x(1)=1.

For example, $\phi_8 \rightarrow GL_2(\mathbb{Re})" alt="\phi_8 \rightarrow GL_2(\mathbb{Re})" /> can be a matrix representation (verify this), which maps the identity of $D_8$ to $2 \times 2$ identity matrix in $GL_2(\mathbb{Re})$, i.e., $\chi(1)=2$, where $\chi$ is the character of $\phi$.

4. Thanks so much!