Beltrametti–Sommese conjecture on effective strictly nef divisors

Let XX be a smooth projective variety and let DD be an effective strictly nef divisor on XX. A divisor DD is strictly nef if DC>0D\cdot C>0 for every curve CC on XX.

Beltrametti–Sommese conjecture. If DKXD-K_X is nef, then DD is ample.

This conjecture concerns when numerical positivity of an effective divisor, together with positivity relative to the canonical divisor, forces ampleness. The source presents it as a conjecture of Beltrametti and Sommese; no resolution is given in the supplied text.

Sources & referencesView supporting material

Primary source

Nikolaos Tsakanikas and Zhixin Xie, “Comparison and uniruledness of asymptotic base loci”, arXiv:2309.01031 (2024).

Additional references

10 papers in this index state this conjecture (2007–2023). The statement above is taken from the most recent of them; the others are arXiv:2306.06985, arXiv:1307.1449, arXiv:1302.1413, arXiv:1105.2415, arXiv:1001.2792, arXiv:0912.1295, arXiv:0910.2785, arXiv:0811.3059, arXiv:0707.4140.

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