Let \(X=S^1\vee S^1\) and \(x_0\in X\) be the attaching point.
- Carefully state van Kampen’s Theorem and use it to compute \(\pi _1(X,x_0)\).
- Find two covering spaces of \(X\) with three sheets; one of which is regular (determining a normal subgroup of \(\pi _1(X,x_0)\)) and the other of which is irregular.