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Surgeries modify manifolds by removing and replacing submanifolds. Properly constructed surgeries preserve invariants like homology groups and fundamental groups.

Theorem 3.1 (Invariant Preservation)
If φ: M → M' is a continuous, bijective transformation with continuous inverse, then all topological invariants of M are preserved in M'.

Towards A Proof

Since φ is a homeomorphism, open sets map to open sets bijectively. Therefore, properties like compactness, connectivity, and genus are preserved by the continuity and invertibility of the map.

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