$\mathbb{Z}_{2}$-equivariant Heegaard Floer cohomology of knots in $S^{3}$ as a strong Heegaard invariant

Abstract

The $\mathbb{Z}_{2}$-equivariant Heegaard Floer cohomlogy $\widehat{HF}_{\mathbb{Z}_{2}}(\Sigma(K))$ of a knot $K$ in $S^{3}$, constructed by Hendricks, Lipshitz, and Sarkar, is an isotopy invariant which is defined using bridge diagrams of $K$ drawn on a sphere. We prove that $\widehat{HF}_{\mathbb{Z}_{2}}(\Sigma(K))$ can be computed from knot Heegaard diagrams of $K$ and show that it is a strong Heegaard invariant. As a topolocial application, we construct a transverse knot invariant $\hat{\mathcal{T}}_{\mathbb{Z}_{2}}(K)$ as an element of $\widehat{HFK}_{\mathbb{Z}_{2}}(\Sigma(K),K)$, which is a refinement of $\widehat{HF}_{\mathbb{Z}_{2}}(\Sigma(K))$, and show that it is a refinement of both the LOSS invariant $\hat{\mathcal{T}}(K)$ and the $\mathbb{Z}_{2}$-equivariant contact class $c_{\mathbb{Z}_{2}}(\xi_{K})$.