Conjecture on the decreasing proportion of toric Fano varieties with exceptional collections

For each positive integer dd, let f(d)f(d) be the proportion of smooth projective toric Fano dd-folds for which the Hanlon–Hicks–Lazarev resolution of the diagonal yields a full strong exceptional collection of line bundles. The known values are

11=f(1)=f(2)=55,f(3)=1618,f(4)=72124,f(5)=300866.\frac{1}{1}=f(1)=f(2)=\frac{5}{5},\qquad f(3)=\frac{16}{18},\qquad f(4)=\frac{72}{124},\qquad f(5)=\frac{300}{866}.

Monotonicity and vanishing conjecture. The function f(d)f(d) is strictly monotone decreasing for d>1d>1, and

limdf(d)=0.\lim_{d\rightarrow\infty} f(d)=0.

This conjecture extrapolates from the computed proportions in dimensions one through five. It predicts that the proportion of smooth projective toric Fano varieties detected by this resolution as having such exceptional collections decreases strictly in higher dimensions and tends to zero; no resolution of the conjecture is stated.

Sources & referencesView supporting material

Primary source

Reginald Anderson, “Exceptional Collections for Toric Fano Fivefolds”, arXiv:2512.11801 (2025).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.