Past exam of the mathematics course of the University of Cambridge 2023 iii Paper 114 1 iii Solution 2026-09-28
The quotient is the mapping torus ofA mapping torus of a cellular map has a finite CW structure. On integral homology, is on and and is on . The Wang sequence therefore givesOver , the map is the identity. The Wang sequence splits as vector spaces into one copy of and one copy of , yielding