Let \(X\) be a topological space and \(x_0\in X\) a basepoint.
- Define \(\pi _1(X,x_0)\) (describe it as a set and define the group operation; you don’t have to prove that it is well defined or that it is a group).
- If \(X\) is path-connected and \(x_1\in X\) prove that \(\pi _1(X,x_0)\cong \pi _1(X,x_1)\) (write down an explicit isomorphism and check that it works).