2 problems

Let $\mathcal C\subset \mathbf{T}^2$ be a smooth curve with non-zero curvature, and let $F$ be a toral eigenfunction with eigenvalue parameter $\lambda$. Write $\mathcal Z(F)$ for…

Positivity conjecture. The strict inequality $c_{q;d}>0$ holds for every pair $(d,q)$ with $d,q\geq 2$.