Torus surguries on knot traces
Kai Nakamura
TL;DR
$The paper develops a unified framework for studying knot traces via 4D torus surgeries, by interpreting Osoinach's annulus twists as torus surgeries on knot-trace exteriors $X_0(J_0)$ and then applying the rich theory of torus surgery to obtain exotic 4-manifolds, exotic traces, and potential counterexamples to the smooth 4D Poincaré conjecture. The main technical bridge, Theorem that annulus twists extend to torus surgeries, enables re-deriving Manolescu–Piccirillo homotopy-sphere standardness in this setting and extends to elliptic surfaces with the notion of $H$-slice. The work yields several novel outcomes: (i) infinite families of mutually exotic knot traces related by annulus twisting with concordance and identical shake-genus/genus-function data, (ii) exotic Stein traces and Legendrian realizations with identical boundaries, (iii) a hidden fishtail symmetry clarifying when annulus twists extend to trace diffeomorphisms and (iv) new potential candidates for SPC4 counterexamples built from torus surgery on Conway knot traces. Overall, the approach broadens the toolbox for constructing and distinguishing exotic 4-manifolds through knot-trace surgery and raises deep questions about sliceness, concordance, and the boundaries of Stein and symplectic fillings.$
Abstract
We initiate the study of torus surgeries on knot traces. Our key technical insight is realizing the annulus twisting construction of Osoinach as a torus surgery on a knot trace. We present several applications of this idea. We find exotic elliptic surfaces that can be realized as surgery on null-homologously embedded traces in a manner similar to that proposed by Manolescu and Piccirillo. Then we exhibit exotic traces with novel properties and improve upon the known geography for exotic Stein fillings. Finally, we construct new potential counterexamples to the smooth 4-dimensional Poincaré Conjecture.
