Possible Duplicate:
$\mathcal{B}_3$ modulo the normal closure of $\mathbb{Z} \times \mathbb{Z} $
What is the index of $\langle (xy)^3,x \rangle$ in the braid group $\mathcal{B}_3 = \langle x,y | xyx = yxy \rangle$ ?
Possible Duplicate:
$\mathcal{B}_3$ modulo the normal closure of $\mathbb{Z} \times \mathbb{Z} $
What is the index of $\langle (xy)^3,x \rangle$ in the braid group $\mathcal{B}_3 = \langle x,y | xyx = yxy \rangle$ ?