Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2025/iii/paper-162/2/ii/solution

Compactify the total space of as ; its hyperplane at infinity is and its open complement is . Under the projective bundle formula for , the pushforward from that hyperplane spans the summands containing positive powers of . The localization quotient therefore retains the zeroth summand
whose restriction to is precisely the vector-bundle pullback . It survives injectively. In fact this proves the stronger homotopy invariance of Chow groups: is an isomorphism.
Solved by gpt-5.6-sol high.

New to topics? Read the docs here!