Zobrazeno 1 - 10
of 246
pro vyhledávání: '"SHIMADA, ICHIRO"'
Autor:
Shimada, Ichiro
We investigate the topology of a double cover of a complex affine plane branching along a nodal real line arrangement. We define certain topological 2-cycles in the double plane using the real structure of the arrangement, and calculate their interse
Externí odkaz:
http://arxiv.org/abs/2401.15929
Autor:
Shimada, Ichiro
A line arrangement of a smooth cubic surface is a subset of the set of lines on the cubic surface. We define a notion of Zariski pairs of line arrangements on general cubic surfaces, and make the complete list of these Zariski pairs.
Comment: 8
Comment: 8
Externí odkaz:
http://arxiv.org/abs/2401.15930
Autor:
Shimada, Ichiro
We present a method to calculate the action of the Mordell-Weil group of an elliptic K3 surface on the numerical N\'eron-Severi lattice of the K3 surface. As an application, we compute a finite generating set of the automorphism group of a K3 surface
Externí odkaz:
http://arxiv.org/abs/2210.01328
Autor:
Shimada, Ichiro
We investigate Zariski multiples of plane curves $Z_1, \dots, Z_N$ such that each $Z_i$ is a union of a smooth quartic curve, some of its bitangents, and some of its 4-tangent conics. We show that, for plane curves of this type, the deformation types
Externí odkaz:
http://arxiv.org/abs/2209.11938
Autor:
Shimada, Ichiro
By constructing explicit examples, we show that the method of Quebbemann yields many isomorphism classes of extremal lattices of rank 64. Many of these examples have no non-trivial automorphisms.
Comment: 12 pages. A few typos are corrected
Comment: 12 pages. A few typos are corrected
Externí odkaz:
http://arxiv.org/abs/2106.04828
Autor:
Brandhorst, Simon, Shimada, Ichiro
We calculate the automorphism group of certain Enriques surfaces. The Enriques surfaces that we investigate include very general $n$-nodal Enriques surfaces and very general cuspidal Enriques surfaces. We also describe the action of the automorphism
Externí odkaz:
http://arxiv.org/abs/2012.10622
Let $f$ be an automorphism of a complex Enriques surface $Y$ and let $p_f$ denote the characteristic polynomial of the isometry $f^*$ of the numerical N\'eron-Severi lattice of $Y$ induced by $f$. We apply a modification of McMullen's method to prove
Externí odkaz:
http://arxiv.org/abs/1909.10813
Autor:
Dolgachev, Igor, Shimada, Ichiro
We describe a set of generators and defining relations for the group of birational automorphisms of a general 15-nodal quartic surface in the complex projective 3-dimensional space.
Comment: 27 papes
Comment: 27 papes
Externí odkaz:
http://arxiv.org/abs/1908.05390
Autor:
Brandhorst, Simon, Shimada, Ichiro
We classify all primitive embeddings of the lattice of numerical equivalence classes of divisors of an Enriques surface with the intersection form multiplied by 2 into an even unimodular hyperbolic lattice of rank 26. These embeddings have a property
Externí odkaz:
http://arxiv.org/abs/1903.01087