Kinosaki Algebraic Geometry Symposium 2026

26 Oct 2026, 09:00 → 30 Oct 2026, 18:00 Asia/Tokyo

Dates: 26 - 30 Oct 2026

Overview:

Algebraic geometry has a long history, encompassing a wide range of topics. Reflecting this diversity, research meetings in algebraic geometry are often organized around specialized subfields, bringing together experts in each area. At the same time, however, it is equally important to hold larger-scale meetings that are not restricted to specific topics, in order to facilitate the exchange of ideas and techniques across different areas.
In Japan, the Kinosaki Algebraic Geometry Symposium has played such a role for over half a century.
This year, the Kinosaki Algebraic Geometry Symposium aims to further strengthen this role by bringing together researchers from diverse areas of algebraic geometry for broad and active discussions, while maintaining its traditional scope. In particular, in collaboration with the Kavli IPMU, the symposium will place special emphasis on fostering deeper interaction between international researchers based in Japan and the Japanese algebraic geometry community.

Invited Speakers:

Alastair Craw (Bath)

Linghu Fan (Kavli IPMU)

Reimi Irokawa (NTT)

Shihoko Ishii (Tokyo)

Ryo Ishizuka (Science Tokyo)

Mikhail Kapranov (Kavli IPMU)

Nao Moriyama (Kyoto)

Anya Nordskova (Kavli IPMU)

Yuji Odaka (RIMS)

Hyeonjun Park (KIAS)

Franco Rota (Université Paris-Saclay)

Matthias Schütt (Hannover)

Shou Yoshikawa (Science Tokyo)

 

 

Organizing Committee:

 

• Wahei Hara (Tokai)
• Yukari Ito (Kavli IPMU)
• Tasuki Kinjo (RIMS)

If you have any questions or requests, please email to kinosaki2026ag [at] gmail.com .

Program:

The program is available here.

Registration:

Conference registration is now open. Everyone who plans to attend the conference is required to register. The registration form also includes an option to register for the banquet (see below).

The deadline to register is September 24 at 23:59 JST. 

Registration for guests staying at Tsutaya Ryokan is now closed. If you would like to attend the conference and have not yet arranged accommodation, please make your own accommodation arrangements.

• Please note that, unfortunately, we cannot offer visa assistance for general attendees.

 

Conference Hotel:

The organizers will arrange accommodation at Tsutaya Ryokan for up to  50 registered participants. Please note the following:

1. Accommodation costs must be covered by the participants themselves; they will not be covered by the organizers. The cost is 16,930 JPY per person per night. (Only for Wednesday night, it will be 13,080 JPY per person per night.)
2. Depending on the number of registrations, we may ask some participants to arrange their own accommodation at a different hotel. For early-career researchers, priority for accommodation at Tsutaya Ryokan will be given to those presenting posters.
3. Tsutaya Ryokan is a traditional Japanese inn, and most rooms are designed for families rather than individual guests, with only a limited number of rooms available. Therefore, all participants staying at Tsutaya Ryokan will be asked to share rooms with others.
4. Please note that Tsutaya Ryokan may not be able to accommodate special dietary requests. In particular, vegetarian meals cannot be provided. Participants staying at Tsutaya Ryokan may choose to have their meals at nearby convenience stores or restaurants instead of the meals provided by the ryokan. In that case, no meal charges will apply.

 

Banquet:

A banquet is planned for Wednesday, October 28.

Venue: Okesho Sengyo ( https://okesyo.com )
Time: From 5:00 p.m.
Budget: approximately 8,000 JPY per person.

The banquet will be open to all workshop participants, regardless of whether they are staying at Tsutaya Ryokan. 

You can now register through the conference registration form. The deadline to register is September 24 at 23:59 JST. 

Conference Venue:

Lecture Hall, Kinosaki International Art Centre, 

1062 Yushima, Kinosaki-cho, Toyooka-shi, Hyogo 669-6101, Japan.

 

kinosaki2026-program.pdf

Tuesday 27 October

1 Numerically and cohomologically trivial automorphisms of elliptic surfaces

Numerically and cohomologically trivial automorphisms form a classical topic
in algebraic geometry, especially for algebraic surfaces. I will focus on the
case of complex elliptic surfaces of Kodaira dimension one, which features
some surprising results, also in view of past claims. Much of this will be
motivated by the instructive case of Enriques surfaces.
(Joint work with Catanese, Frapporti, Glei\ss ner and Liu)

Speaker: Matthias Schütt (Leibniz Universität Hannover)

2 Hybrid dynamics of cohomologically hyperbolic automorphisms of complex projective surfaces

We study degenerating families of hyperbolic dynamics over complex projective
surfaces by means of the theory of hybrid spaces by Boucksom, Favre, and
Jonsson. For an analytic family of hyperbolic automorphisms
$\{f_t\colon X_t\to X_t\}_{t\in\mathbb{D}^*}$ over projective surfaces $X_t$
that is possibly meromorphically degenerating at the origin, we consider the
family of invariant measures $\{\eta_t\}$ on $X_t$ constructed by Cantat.
The family $f_t$ induces a hyperbolic automorphism
$f^{\mathrm{an}}_{\mathbb{C}((t))}\colon X^{\mathrm{an}}_{\mathbb{C}((t))}\to X^{\mathrm{an}}_{\mathbb{C}((t))}$
over the induced non-archimedean projective surface, where we also have a
measure $\eta_0$ by Filip. Our main theorem states the weak convergence of
$\{\eta_t\}$ to $\eta_0$ as $t\to0$ over the induced so-called hybrid space.

Speaker: Reimi Irokawa (NTT)

3 Hodge–Tate splitting and Akizuki–Nakano vanishing in positive characteristic I

For smooth projective varieties in characteristic zero, Hodge-to-de Rham
spectral sequence degenerates and Akizuki--Nakano vanishing theorem holds.
However, both statements can fail in positive and mixed characteristic.
Deligne and Illusie proved that, for a smooth variety $X$ in characteristic
$p$ admitting a $W_2$-lifting and satisfying $p>\dim X$, de Rham complex
decomposes and this implies the above degenerations and vanishings. More
recently, Petrov used the geometry of the de Rham stack to obtain such a
decomposition for smooth quasi-$F$-split varieties without any dimension
restriction.

When such a decomposition exists, the natural map to the de Rham complex
admits a retraction. In this talk, I will explain how, conversely, the
existence of such a retraction, which we call Hodge--Tate splitting, implies
a decomposition of the de Rham complex by using the geometry of de Rham
stacks. I will also discuss the corresponding logarithmic theory for SNC
divisors and an application to mixed characteristic.
This is joint work with Shou Yoshikawa.

Speaker: Ryo Ishizuka (Institute of Science Tokyo)

4 Hodge–Tate splitting and Akizuki–Nakano vanishing in positive characteristic II

Following the talk ``Hodge--Tate splitting and Akizuki--Nakano vanishing I'',
I will continue the discussion of Hodge--Tate splitting, focusing in
particular on examples and applications. I will present characterizations
of Hodge--Tate splitting for Fano and Calabi--Yau varieties, and discuss
when Hodge--Tate splitting is preserved under various algebraic
constructions, including blow-ups, projective bundles, and linearly
reductive quotients. I will also explain its relation to quasi-$F$-splitting.

Speaker: Shou Yoshikawa (Institute of Science Tokyo)

Wednesday 28 October

5 Subtleties in the minimal model theory for log surfaces without assuming Q-factoriality or log canonicity

$\mathbb{Q}$-factoriality or log canonicity}
The minimal model program (MMP) and the abundance conjecture are central
problems in birational geometry. The MMP for log surfaces holds under
standard assumptions, such as $\mathbb{Q}$-factoriality or log canonicity.
In this talk, we show that the MMP for log surfaces fails in general. On
the other hand, intriguingly, we also mention that the abundance theorem
still holds for log surfaces in such a setting where the MMP fails. This
talk is based on the author's preprint (arXiv:2602.00732) and joint work
with Makoto Enokizono (arXiv:2609.12478).

Speaker: Nao Moriyama (Kyoto U.)

6 Canonical torus action on symplectic singularities

For symplectic singularities, we reveal the presence of intrinsic canonical
(local) action of $\mathbb{H}^*$ on each of them, where $\mathbb{H}$ is the
Hamilton quaternion, though conditionally for now. Its subaction of
$\mathbb{C}^*$ satisfies a certain canonicity
("K-polystability"/hyperKähler structure) which we explain. Weaker version
was predicted by Kaledin decades ago. Joint with Y. Namikawa.
cf., arXiv:2503.15791

Speaker: Yuji Odaka (RIMS, Kyoto U.)

7 On Kawamata–Viehweg and Lipman Vanishings

The birational Kawamata--Viehweg vanishing theorem (KVV for short) is known
to hold in considerable generality in equal characteristic zero. By contrast,
it fails in general in positive characteristic. Nevertheless, it may still
hold for certain types of birational morphisms.

In his 2008 paper in the Michigan Mathematical Journal, Lipman studied
sequences of blow-ups at closed points over regular schemes, including in
mixed characteristic, and stated a vanishing theorem that we call
"Lipman's goal statement". This can be viewed as a special form of KVV.
Although the argument in that paper is incorrect, this does not imply that
the goal statement itself is false.

In this talk, we prove the goal statement under either of the assumptions,
(1) the schemes are essentially of finite type over a perfect field $k$ of
characteristic $p\geq N-1$, where $N$ is their dimension, or
(2) the schemes have dimension at most $3$.

Speaker: Shihoko Ishii (U. of Tokyo)

Thursday 29 October

8 Infinitely many braid group orbits

I will present an example of a smooth projective variety $X$ for which the
braid group action on the set of full exceptional collections in $D^b(X)$
is not transitive and in fact has infinitely many orbits. Although the idea
behind the construction is quite simple and the example is not at all
exotic, this is the first case where such non-transitivity has been observed
in the realm of smooth projective varieties. If time permits, I will also
comment on another curious "disconnectedness" phenomenon. Namely, I will
try to explain why the space of Bridgeland stability conditions
$\operatorname{Stab}(X)$ on $X$ has infinitely many connected components.

Speaker: Anya Nordskova (Kavli IPMU)

9 The wild age of linear p-cyclic quotient singularities

In this talk, we consider the quotient singularities associated to some
special linear actions of finite groups without pseudo-reflections. In
characteristic $0$, the age grading on the group, which relies on the
existence of the primitive roots of unity, is useful to study the properties
of the quotient singularities. On the other hand, when the characteristic
$p$ is positive, the age grading cannot be defined on the $p$-subgroups.
Instead, the invariant $D_V$ was introduced by Yasuda to study the linear
$p$-cyclic quotients. After a historical overview to the invariant $D_V$,
we will illustrate its role through recent developments, including the
criterion for cyclic quotients to be terminal or canonical, the construction
of crepant models, and the predicting formulas for the Euler
characteristics of crepant resolutions. This talk is based in part on
joint work with Hongmin Li.

Speaker: Linghu Fan (Kavli IPMU)

10 Formal neighborhoods of curves in Calabi–Yau threefolds

An important question in birational and enumerative geometry is that of
contractibility of curves in higher dimensional varieties. Motivated by
this, I will focus on rational curves in Calabi--Yau threefolds: the most
recent results in this direction tie contractibility with non-commutative
geometry and deformation theory, through a local model for the formal
neighborhood of the curve.

In particular, Brown and Wemyss compute the non-commutative deformation
theory of curves whose local model has a specific form (introduced by
Katz). I will give a necessary geometric condition for a curve to admit a
formal neighborhood in Katz form. This is also sufficient for curves whose
normal bundle is $(-1,-1)$ and $(-2,0)$. I will then present several
examples, either new or revisiting construction in the literature through
this lens. This is work in progress, joint with M.\ Wemyss.

Speaker: Franco Rota (Université Paris-Saclay)

11 The Cautis–Logvinenko conjecture for 3-fold NCCRs

For a finite subgroup $G$ of $\operatorname{SL}(3,\mathbb{C})$, the
$G$-Hilbert scheme is a crepant resolution of the quotient singularity
$\mathbb{C}^3/G$, and the universal family induces a derived equivalence
between coherent sheaves on $G$-Hilb and $G$-equivariant coherent sheaves
on $\mathbb{C}^3$. In 2009, Cautis and Logvinenko conjectured that this
equivalence sends the simple $G$-sheaves, one for each nontrivial irreducible
representation of $G$, to pure sheaves on $G$-Hilb. I will describe how the
recent proof of this conjecture with Lin and Yamagishi generalises naturally
to all 3-fold noncommutative crepant resolutions for which the vertex simple
modules exist.

Speaker: Alastair Craw (U. of Bath)

Friday 30 October

12 Shifted Lagrangian classes

Modern enumerative invariants, such as Gromov--Witten invariants and
Donaldson--Thomas invariants, are defined through the virtual classes.
In this talk, I will introduce Lagrangian classes, whose existence was
conjectured by Joyce, as a generalization of the virtual classes via shifted
symplectic geometry. As applications, I will explain the construction of
(1) cohomological Hall algebras for 3-Calabi--Yau categories;
(2) cohomological field theories for gauged linear sigma models;
(3) relative Donaldson--Thomas theory for 4-dimensional log Calabi--Yau pairs;
(4) algebraic Fukaya categories for hyperkahler varieties. This is joint
work in progress with Adeel Khan, Tasuki Kinjo, and Pavel Safronov.

Speaker: Hyeonjun Park (KIAS)

13 Supersymmetry, differential operators of infinite order and theta functions

Differential operators of infinite order (DOI) are series in derivatives
which converge and define local operators of analytic functions. For
example, $\exp(d/dx)$ is not allowed but $\cos\sqrt{d/dx}$ is. Starting
from 1972, Sato, Kashiwara, Kawai, Takei, Yoshida and others developed a
characterization of $\theta(T)$, the Riemann theta-zerovalue, by a system
of DOI in modular variables alone, thus deducing modularity from local
properties.

In the talk I will explain how supersymmetry gives rise to DOI and how a
supersymmetric thickening of the Siegel upper half plane gives a natural
construction of the modular invariant system of DOI for $\theta(T)$.

Speaker: Mikhail Kapranov (Kavli IPMU)