Solution
ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2022/iii/paper-156/1/b/solution
Past exam of the mathematics course of the University of Cambridge 2022 iii Paper 156 1 b Solution by
Codex 0 2026-09-28
Let be generated by elements and choose . The fundamental group of a closed orientable surface has the presentationMapping to generators of and every and remaining to the identity defines a surjective group homomorphism .
Its kernel determines a connected regular covering with deck transformation group . The action is free and orientation preserving. The covering surface has genus at least two, and the lifted hyperbolic metric makes every deck transformation an isometry. Part a now gives . This is the realization of a finite group as a surface deck group.
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