Cone conjecture

For every projective klt pair (X,Δ)(X,\Delta) such that KX+Δ≡0K_X+\Delta\equiv 0, the automorphism group Aut⁡(X,Δ)\operatorname{Aut}(X,\Delta) acts on the nef cone Nef⁡(X)⊂N1(X)R\operatorname{Nef}(X)\subset N^1(X)_{\mathbb{R}} with a rational polyhedral fundamental domain. Moreover, the birational automorphism group Bir⁡(X,Δ)\operatorname{Bir}(X,\Delta) acts on the movable cone Mov⁡(X)⊂N1(X)R\operatorname{Mov}(X)\subset N^1(X)_{\mathbb{R}} with a rational polyhedral fundamental domain; that is, there should exist rational polyhedral cones Πnef⊂Nef⁡(X)\Pi_{\mathrm{nef}}\subset\operatorname{Nef}(X) and Πmov⊂Mov⁡(X)\Pi_{\mathrm{mov}}\subset\operatorname{Mov}(X) such that Nef⁡(X)=⋃g∈Aut⁡(X,Δ)gΠnef\operatorname{Nef}(X)=\bigcup_{g\in\operatorname{Aut}(X,\Delta)}g\Pi_{\mathrm{nef}} and Mov⁡(X)=⋃g∈Bir⁡(X,Δ)gΠmov\operatorname{Mov}(X)=\bigcup_{g\in\operatorname{Bir}(X,\Delta)}g\Pi_{\mathrm{mov}}, with translates having disjoint interiors.

References

Additional references

Progress summary

Refreshed
Claimed progress

A new paper reports progress for a narrow family of Calabi–Yau mirror spaces, but the general conjecture remains unresolved.

The cone conjecture predicts a finite, polyhedral description of birationally defined cones for Calabi–Yau-type varieties, and remains open in general. The standard formulation is associated with Kawamata, Morrison, and Totaro.

Known results

  • Klt Calabi–Yau pairs: the conjecture is proved in dimension 22 (2009).
  • Certain complete-intersection Calabi–Yau threefolds of Picard number two: the movable-cone version is verified (2021).
  • Specified complete-intersection Calabi–Yau threefolds in ruled Fano manifolds: the movable cone is rational polyhedral (2022).
  • Schoen varieties and related examples admit rational-polyhedral fundamental domains in the stated settings (2022–2025).

2026 article on Fano-threefold mirrors

Jennifer Li’s article, “On the cone conjecture for log Calabi–Yau mirrors of Fano 3-folds,” addresses a specified mirror family and reports a finiteness result for codimension-one faces of its movable cone under stated hypotheses. This is a special-case advance, not a solution of the full conjecture; the retrieved publication metadata does not give enough theorem detail for independent assessment.

Current status (as of September 2026): Special cases are established, and Li’s newly indexed article indicates further progress for log Calabi–Yau mirrors of Fano threefolds, but the general cone conjecture remains open.

Sources

Solutions 0

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