Fix integers \(n\ge 1\) and \(m\ge 1\).
- Construct a connected space \(X\) such that \[ \widetilde {H}_r(X;\mathbb {Z})= \begin {cases} 0 & \text {if } r\ne n,\\ \mathbb {Z}/m & \text {if } r=n. \end {cases} \] (Here \(\widetilde {H}\) denotes reduced homology.)
- For any connected space \(X\) satisfying the conclusion of part (a), compute the groups \(H_r(X;\mathbb {Z}/2)\) for all \(r\ge 0\).