15 citations · 59 across the 20 of their papers we have counts for
12 papers · 1 filter
Free automorphism groups of K3 surfaces with Picard number 3
Kenji Hashimoto, Kwangwoo Lee
It is known that the automorphism group of any projective K3 surface is finitely generated [24]. In this paper, we consider a certain kind of K3 surfaces with Picard number 3 whose…
Extensions of maximal symplectic actions on K3 surfaces
Simon Brandhorst, Kenji Hashimoto
We classify pairs consisting of a complex K3 surface and a finite group such that the subgroup consisting of symplectic automorphisms is a…
Examples of non-Kähler Calabi-Yau 3-folds with arbitrarily large
Kenji Hashimoto, Taro Sano
We construct non-Kähler simply connected Calabi-Yau 3-folds with arbitrarily large 2nd Betti numbers by smoothing normal crossing varieties with trivial dualizing sheaves.
Reconstruction of general elliptic K3 surfaces from their Gromov-Hausdorff limits
Kenji Hashimoto, Kazushi Ueda
We show that a general elliptic K3 surface with a section is determined uniquely by its discriminant, which is a configuration of 24 points on the projective line. It follows that…
K3 surfaces with Picard number 2, Salem polynomials and Pell equation
Kenji Hashimoto, JongHae Keum, Kwangwoo Lee
If an automorphism of a projective K3 surface with Picard number 2 is of infinite order, then the automorphism corresponds to a solution of Pell equation. In this paper, by solving…
Calabi-Yau threefolds of type K (II): Mirror symmetry
Kenji Hashimoto, Atsushi Kanazawa
A Calabi-Yau threefold is called of type K if it admits an étale Galois covering by the product of a K3 surface and an elliptic curve. In our previous paper, based on Oguiso-Sakura…
On a certain generalization of triangle singularities
Kenji Hashimoto, Hwayoung Lee, Kazushi Ueda
Triangle singularities are Fuchsian singularities associated with von Dyck groups, which are index two subgroups of Schwarz triangle groups. Hypersurface triangle singularities are…
Calabi-Yau threefolds of type K (I): Classification
Kenji Hashimoto, Atsushi Kanazawa
Any Calabi-Yau threefold X with infinite fundamental group admits an étale Galois covering either by an abelian threefold or by the product of a K3 surface and an elliptic curve. W…
The ring of modular forms for the even unimodular lattice of signature (2,10)
Kenji Hashimoto, Kazushi Ueda
We show that the ring of modular forms with characters for the even unimodular lattice of signature (2,10) is generated by forms of weights 4, 10, 12, 16, 18, 22, 24, 28, 30, 36, 4…
Modular surfaces associated with toric K3 hypersurfaces
Kenji Hashimoto, Atsuhira Nagano, Kazushi Ueda
We give detailed descriptions of the period maps of two 2-parameter families of anti-canonical hypersurfaces in toric 3-folds. One of them is related to a Hilbert modular surface,…
Finite Symplectic Actions on the K3 Lattice
Kenji Hashimoto
In this paper, we study finite symplectic actions on K3 surfaces X, i.e. actions of finite groups G on X which act on H^{2,0}(X) trivially. We show that the action on the K3 lattic…
Period map of a certain K3 family with an S5-action
Kenji Hashimoto, Tomohide Terasoma
In this paper, we study the period map of a certain one-parameter family of quartic K3 surfaces with an S5-action. We construct automorphic forms on the period domain as the pull-b…