Relative Invertibility and Full Dualizability of Finite Braided Tensor Categories

Abstract

Fix a finite symmetric tensor category $\mathcal{E}$ over an algebraically closed field. We derive an $\mathcal{E}$-enriched version of Shimizu's characterizations of non-degeneracy for finite braided tensor categories. In order to do so, we consider, associated to any $\mathcal{E}$-enriched finite braided tensor category $\mathcal{A}$ satisfying a mild technical assumption, a Hopf algebra $\mathbb{F}_{\mathcal{E}/\mathcal{A}}$ in $\mathcal{A}$. This is a generalization of Lyubashenko's universal Hopf algebra $\mathbb{F}_{\mathcal{A}}$ in $\mathcal{A}$. In fact, we show that there is a short exact sequence $\mathbb{F}_{\mathcal{E}}\rightarrow\mathbb{F}_{\mathcal{A}}\rightarrow\mathbb{F}_{\mathcal{E}/\mathcal{A}}$ of Hopf algebras in $\mathcal{A}$, and that the canonical pairing on $\mathbb{F}_{\mathcal{A}}$ descends to a pairing $\omega_{\mathcal{E}/\mathcal{A}}$ on $\mathbb{F}_{\mathcal{E}/\mathcal{A}}$. We prove that $\mathcal{A}$ is $\mathcal{E}$-non-degenerate, i.e.\ its symmetric center is exactly $\mathcal{E}$, if and only if the pairing $\omega_{\mathcal{E}/\mathcal{A}}$ is non-degenerate. We then use the above characterization to show that an $\mathcal{E}$-enriched finite braided tensor category is invertible in the Morita 4-category of $\mathcal{E}$-enriched pre-tensor categories if and only if it is $\mathcal{E}$-non-degenerate. As an application of our relative invertibility criterion, we extend the full dualizability result of Brochier-Jordan-Snyder by showing that a finite braided tensor category is fully dualizable as an object of the Morita 4-category of braided pre-tensor categories if its symmetric center is separable.