Kawamata–Morrison cone conjecture for K-trivial fiber spaces

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Let f:X→Sf:X\to S be a KK-trivial fiber space, meaning a normal Q\mathbb Q-factorial klt pair (X,Δ)(X,\Delta) endowed with a proper surjective morphism with connected fibres such that KX+Δ≡f0K_X+\Delta\equiv_f0. Write Mov⁡‾e(X/S):=Mov⁡‾(X/S)∩Eff⁡(X/S)\overline{\operatorname{Mov}}^e(X/S):=\overline{\operatorname{Mov}}(X/S)\cap\operatorname{Eff}(X/S) and Nef⁡e(X/S):=Nef⁡(X/S)∩Eff⁡(X/S)\operatorname{Nef}^e(X/S):=\operatorname{Nef}(X/S)\cap\operatorname{Eff}(X/S). Kawamata–Morrison cone conjecture. There exists a rational polyhedral cone Π\Pi such that

Mov⁡‾e(X/S)=⋃g∈PsAut⁡(X/S)g∗Π,\overline{\operatorname{Mov}}^e(X/S)=\bigcup_{g\in\operatorname{PsAut}(X/S)}g^*\Pi,

and

Π∘∩(g∗Π)∘=∅\Pi^\circ\cap(g^*\Pi)^\circ=\emptyset

for every g∈PsAut⁡(X/S)g\in\operatorname{PsAut}(X/S), except when g∗=1g^*=1 in GL⁡(N1(X/S))\operatorname{GL}(N^1(X/S)). There also exists a rational polyhedral cone Π′\Pi' satisfying the analogous fundamental-domain conditions for the action of Aut⁡(X/S)\operatorname{Aut}(X/S) on Nef⁡e(X/S)\operatorname{Nef}^e(X/S). The conjecture predicts rational polyhedral fundamental domains for the movable and nef cones; in the source paper, the stated version is proved under the hypotheses described in the abstract, while the supplied span itself gives no resolution status for the general formulation.

References

Primary source

Aurélien Faucher, “The Cone Conjecture for Primitive Symplectic Varieties over a Field of Characteristic Zero and an Application”, arXiv:2512.19656 (2026).

Additional references

13 papers in this index state this conjecture (2012–2025). The statement above is taken from the most recent of them; the others are arXiv:2503.03949, arXiv:2412.15460, arXiv:2410.11987, arXiv:2406.07307, arXiv:2207.11150, arXiv:2112.01352, arXiv:2103.11638, arXiv:2005.04254, arXiv:1601.01273, arXiv:1311.6612, arXiv:1210.1903, arXiv:1206.1649.

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