The rationality conjecture for Siegel–Veech area constants

Let ${\mathcal M}_1$ be a regular $\operatorname{SL}(2,\mathbb R)$-invariant suborbifold in a stratum of Abelian differentials, and let $c_{\operatorname{area}}({\mathcal M}_1)$ be its Siegel–Veech area constant. The rationality conjecture for Siegel–Veech constants. The number

$$\pi^2 c_{\operatorname{area}}({\mathcal M}_1)$$

is rational. This predicts arithmeticity of the normalized area Siegel–Veech constants for all regular invariant suborbifolds; the supplied text does not state whether it has been resolved.