Stability conditions on Calabi-Yau threefolds of type K

Abstract

A Calabi-Yau threefold of type K is a free quotient $X=(S\times E)/G$ of the product of a K3 surface and an elliptic curve. We construct a family of geometric Bridgeland stability conditions on $X$ by using Liu's product construction on $S\times E$ and then inducing along the Galois covering. The family has dimension $2h^{1,1}(X)$, and is disjoint from the $\widetilde{\GL}_2^+(\R)$-orbit of Li's stability conditions. These threefolds carry a K3 fibration, and the pushforward of an object from a smooth K3 fiber is (semi)stable if and only if it is (semi)stable on the K3 surface.