Classification in the Z''13 family

Classify the integer quadruples $(a,b,c,d)$ for which the canonical bundle of the smooth proper toric threefold $Z''_{13}(a,b,c,d)$ is tensor-generating, and determine whether every obstruction throughout this family is an invariant $(-1,-1)$-curve.

Background

The paper constructs two infinite subfamilies of the smooth non-projective toric threefolds Z13′′(a,b,c,d)Z''_{13}(a,b,c,d) whose canonical bundles are tensor-generating for specified parameter values. In one subfamily, the exceptional parameter values are explained by invariant obstructing curves of type (−1,−1)(-1,-1). The authors explicitly leave open the classification for all parameters and whether the same geometric form of obstruction persists throughout the entire family.

References

For which $(a,b,c,d)$ is the canonical bundle of $Z''_{13}(a,b,c,d)$ $\otimes$-generating? In the subfamilies above, every obstruction is an invariant $(-1,-1)$-curve. Is that the case throughout the family?

— Tensor-generating line bundles on toric varieties  (2610.22279 - Ito et al., 15 Oct 2026) in Question q:Z13-general, Section 6.1 (The family Z''13)