activity
20162026
most citedExistence of valuations with smallest normalized volume

57 citations · 268 across the 15 of their papers we have counts for

collaborators

16 papers

math.AG2026

Valuative independence for Calabi--Yau varieties

Harold Blum, Yuchen Liu

We construct valuatively independent bases for the space of sections of an ample line bundle on a log Calabi--Yau pair over a discretely valued field and the space of regular funct…

math.AG2025

Relative stability theory and properness of K-moduli spaces

Harold Blum, Yuchen Liu, Chenyang Xu +1

We define the relative stability threshold of a family of Fano varieties over a DVR and show that it is computed by a divisorial valuation. In the case when the special fiber is K-…

math.AG2024

Good moduli spaces for boundary polarized Calabi-Yau surface pairs

Harold Blum, Yuchen Liu

We construct projective asymptotically good moduli spaces parametrizing boundary polarized CY surface pairs, which are projective slc Calabi-Yau pairs such that is ampl…

math.AG2023★ 3 cited

Moduli of boundary polarized Calabi-Yau pairs

Kenneth Ascher, Dori Bejleri, Harold Blum +4

We develop the moduli theory of boundary polarized CY pairs, which are slc Calabi-Yau pairs such that is ample. The motivation for studying this moduli problem is to co…

math.AG2022★ 3 cited

Convexity of multiplicities of filtrations on local rings

Harold Blum, Yuchen Liu, Lu Qi

We prove that the multiplicity of a filtration of a local ring satisfies various convexity properties. In particular, we show the multiplicity is convex along geodesics. As a conse…

math.AG2021★ 16 cited

The existence of the Kähler-Ricci soliton degeneration

Harold Blum, Yuchen Liu, Chenyang Xu +1

We prove an algebraic version of the Hamilton-Tian Conjecture for all log Fano pairs. More precisely, we show that any log Fano pair admits a canonical two-step degeneration to a r…

math.AG2020★ 10 cited

On properness of K-moduli spaces and optimal degenerations of Fano varieties

Harold Blum, Daniel Halpern-Leistner, Yuchen Liu +1

We establish an algebraic approach to prove the properness of moduli spaces of K-polystable Fano varieties and reduce the problem to a conjecture on destabilizations of K-unstable…

math.AG2019★ 35 cited

Optimal destabilization of K-unstable Fano varieties via stability thresholds

Harold Blum, Yuchen Liu, Chuyu Zhou

We show that for a K-unstable Fano variety, any divisorial valuation computing its stability threshold induces a non-trivial special test configuration preserving the stability thr…

math.AG2019★ 10 cited

Openness of K-semistability for Fano varieties

Harold Blum, Yuchen Liu, Chenyang Xu

In this paper, we prove the openness of K-semistability in families of log Fano pairs by showing that the stability threshold is a constructible function on the fibers. We also pro…

math.AG2019★ 45 cited

Reductivity of the automorphism group of K-polystable Fano varieties

Jarod Alper, Harold Blum, Daniel Halpern-Leistner +1

We prove that K-polystable log Fano pairs have reductive automorphism groups. In fact, we deduce this statement by establishing more general results concerning the S-completeness a…

math.AG2018★ 22 cited

Uniqueness of K-polystable degenerations of Fano varieties

Harold Blum, Chenyang Xu

We prove that K-polystable degenerations of Q-Fano varieties are unique. Furthermore, we show that the moduli stack of K-stable Q-Fano varieties is separated. Together with [Jia17,…

math.AG2018★ 31 cited

Openness of uniform K-stability in families of -Fano varieties

Harold Blum, Yuchen Liu

We show that uniform K-stability is a Zariski open condition in Q-Gorenstein families of Q-Fano varieties. To prove this result, we consider the behavior of the stability threshold…

math.AG2018★ 30 cited

The normalized volume of a singularity is lower semicontinuous

Harold Blum, Yuchen Liu

We show that in any -Gorenstein flat family of klt singularities, normalized volumes are lower semicontinuous with respect to the Zariski topology. A quick consequence…

math.AG2017

Thresholds, valuations, and K-stability

Harold Blum, Mattias Jonsson

Let X be a normal complex projective variety with at worst klt singularities, and L a big line bundle on X. We use valuations to study the log canonical threshold of L, as well as…

math.AG2016★ 57 cited

Existence of valuations with smallest normalized volume

Harold Blum

Li introduced the normalized volume of a valuation due to its relation to K-semistability. He conjectured that over a klt singularity there exists a valuation with smallest normali…

math.AG2016★ 6 cited

On divisors computing MLD's and LCT's

Harold Blum

We show that if a divisor centered over a point on a smooth surface computes a minimal log discrepancy, then the divisor also computes a log canonical threshold. To prove the resul…