Connected sum at infinity and 4-manifolds
We study connected sum at infinity on smooth, open manifolds. This operation requires a choice of proper ray in each manifold summand. In favorable circumstances, the connected sum at infinity operation is independent of ray choices. For each m≥3, we construct an infinite family of pairs of m–manifolds on which the connected sum at infinity operation yields distinct manifolds for certain ray choices. We use cohomology algebras at infinity to distinguish these manifolds.
Calcut, Jack S. and Patrick V. Haggerty. 2014. "Connected sum at infinity and 4-manifolds." Algebraic & Geometric Topology 14: 3281-3303.
Mathematical Sciences Publishers
Algebraic & Geometric Topology
Connected sum at infinity, End sum, Ladder manifold, Cohomology algebra at infinity, Proper homotopy, Direct limit, Stringer sum, Lens space