Two-step weighted-volume degeneration conjecture for Fano fibration germs
Two-step weighted-volume degeneration conjecture for Fano fibration germs
Let be a Fano fibration germ. Let be the relevant space of valuations and let denote the weighted volume. For a valuation , write for the associated graded algebra, and form the schemes and morphisms specified below.
Two-step degeneration conjecture for weighted volume.
- There is a unique minimizer of on , which is quasi-monomial.
- The graded ring is finitely generated and is a finitely generated algebra over .
- Let
Then induces a vector field on which descends to . The natural map and define a K-semistable polarized Fano fibration. Moreover, is uniquely characterized by this K-semistability property. 4. There is an equivariant test configuration degenerating to a unique K-polystable polarized Fano fibration .
The conjecture proposes a canonical algebraic two-step degeneration of a Fano fibration germ, first through weighted-volume minimization and then through a test configuration to a K-polystable object. Its existence, finite generation, uniqueness, and compatibility assertions are open in the stated generality.
Sources & referencesView supporting material
Primary source
Song Sun and Junsheng Zhang, “Kähler-Ricci shrinkers and Fano fibrations”, arXiv:2410.09661 (2025).
Progress summary
Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.
Solutions 0
Sign in to submit a solution.
No solutions have been posted yet.