BIRS Workshop Lecture Videos

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BIRS Workshop Lecture Videos

Spines for spineless 4-manifolds Ruberman, Daniel


A recent paper of Levine-Lidman gives examples of simply connected 4-manifolds $X$, homotopy equivalent to a 2-sphere, that do not admit PL spines. In other words, there is no PL (not necessarily locally flat) embedded sphere in $X$ that is a strong deformation retract of $X$. I will show that a family of the Levine-Lidman examples admit a topological spineâ a locally PL sphere that is a strong deformation retract of $X$. This is joint work with Hee Jung Kim.

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