Borel Complexity of Manifold and Group Classification
Analysis
Key Takeaways
- •Applies descriptive set theory to classify manifolds and groups.
- •Determines Borel complexity of homeomorphism and conjugacy/isometry relations.
- •Provides insights into the possibility of numerical invariants for geometric objects.
- •Establishes the complexity of classifying complete hyperbolic n-manifolds with finitely generated fundamental groups.
“The paper shows that the homeomorphism problem for compact topological n-manifolds is Borel equivalent to equality on natural numbers, while the homeomorphism problem for noncompact topological 2-manifolds is of maximal complexity.”