Paper 1, Section II, H

Algebraic Topology
Part II, 2011

Are the following statements true or false? Justify your answers.

(i) If xx and yy lie in the same path-component of XX, then Π1(X,x)Π1(X,y)\Pi_{1}(X, x) \cong \Pi_{1}(X, y).

(ii) If xx and yy are two points of the Klein bottle KK, and uu and vv are two paths from xx to yy, then uu and vv induce the same isomorphism from Π1(K,x)\Pi_{1}(K, x) to Π1(K,y)\Pi_{1}(K, y).

(iii) Π1(X×Y,(x,y))\Pi_{1}(X \times Y,(x, y)) is isomorphic to Π1(X,x)×Π1(Y,y)\Pi_{1}(X, x) \times \Pi_{1}(Y, y) for any two spaces XX and YY.

(iv) If XX and YY are connected polyhedra and H1(X)H1(Y)H_{1}(X) \cong H_{1}(Y), then Π1(X)Π1(Y)\Pi_{1}(X) \cong \Pi_{1}(Y).