Heegaard Floer homology and concordance bounds on the Thurston norm
arXiv:1806.10562
Abstract
We prove that twisted correction terms in Heegaard Floer homology provide lower bounds on the Thurston norm of certain cohomology classes determined by the strong concordance class of a 2-component link in . We then specialise this procedure to knots in , and obtain a lower bound on their geometric winding number. Furthermore we produce an obstruction for a knot in to have untwisting number 1. We then provide an infinite family of null-homologous knots with increasing geometric winding number, on which the bound is sharp.
With an appendix with Adam Simon Levine; 24 pages, 8 figures; comments welcome! V2: Fixed a few typos, wrong citations and figures, removed a proposition. This version to appear in Transactions of the AMS