Additivity of Heegaard genera of bounded surface sums
نویسندگان
چکیده
Let M be a surface sum of 3-manifolds M1 and M2 along a bounded connected surface F and ∂i be the component of ∂Mi containing F . If Mi has a high distance Heegaard splitting, then any minimal Heegaard splitting of M is the amalgamation of those of M,M and M∗, where M i = Mi \ ∂i × I, and M∗ = ∂1 × I ∪F ∂2 × I. Furthermore, once both ∂i \ F are connected, then g(M) = Min {
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