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Makiko Mase

Publications and source records attributed to Makiko Mase.

16 recordsLinked to original sources
arXiv2023

A note on simple $K3$ singularities and families of weighted $K3$ surfaces

We discuss properties of the Seifert form for simple $K3$ singularities, and of the Picard lattices of families of weighted $K3$ surfaces. We study a collection $\mathcal{M}_{(ρ,\,δ)}$ of $K3$ surfaces polarized by their Picard lattices that are in the set $\mathcal{L}_{(ρ,\,δ)}$ of certain lattices. We also report a numerical formula that relates the Seifert form for the singularities and the Picard lattice of the family.

math.AG↗
arXiv2022

Mirror constructions for K3 surfaces from bimodal singularities

We study lattice polarizations of five exceptional pairs of families of K3 surfaces obtained via compactifications of strange dual pairs of bimodal singularities. We show that the polarizations induced by embedding these paired families in paired toric varieties obtained from polar dual reflexive polytopes cannot be mirror lattices and identify mirror sublattices.

math.AG↗
arXiv2021

The combinatorics of weight systems and characteristic polynomials of isolated quasihomogeneous singularities

A paper of the first author and Zilke proposed seven combinatorial problems around formulas for the characteristic polynomial and the exponents of an isolated quasihomogeneous singularity. The most important of them was a conjecture on the characteristic polynomial. Here the conjecture is proved, and some of the other problems are solved, too. In the cases where also an old conjecture of Orlik on the integral monodromy holds, this has implications on the automorphism group of the Milnor lattice. The combinatorics used in the proof of the conjecture consists of tuples of orders on sets $\{0,1,...,n\}$ with special properties and may be of independent interest.

math.CO↗
arXiv2020

The integral monodromy of isolated quasihomogeneous singularities

The integral monodromy on the Milnor lattice of an isolated quasihomogeneous singularity is subject of an almost untouched conjecture of Orlik from 1972. We prove this conjecture for all iterated Thom-Sebastiani sums of chain type singularities and cycle type singularities. The main part of the paper is purely algebraic. It provides tools for dealing with sums and tensor products of ${\mathbb Z}$-lattices with automorphisms of finite order and with cyclic generators. The calculations are involved. They use fine properties of unit roots, cyclotomic polynomials, their resultants and discriminants.

math.AG↗
arXiv2020

The integral monodromy of the cycle type singularities

The middle homology of the Milnor fiber of a quasihomogeneous polynomial with an isolated singularity is a ${\mathbb Z}$-lattice and comes equipped with an automorphism of finite order, the integral monodromy. Orlik (1972) made a precise conjecture, which would determine this monodromy in terms of the weights of the polynomial. Here we prove this conjecture for the cycle type singularities. A paper of Cooper (1982) with the same aim contained two mistakes. Still it is very useful. We build on it and correct the mistakes. We give additional algebraic and combinatorial results.

math.AT↗
arXiv2019

Families of K3 surfaces and curves of (2,3)-torus type

We study families of $K3$ surfaces obtained by double covering of the projective plane branching along curves of $(2,3)$-torus type. In the first part, we study the Picard lattices of the families, and a lattice duality of them. In the second part, we describe a deformation of singularities of Gorenstein $K3$ surfaces in these families.

math.AG↗
arXiv2017

A mirror duality for families of $K3$ surfaces associated to bimodular singularities

Ebeling and Ploog \cite{EbelingPloog} studied a duality of bimodular singularities which is part of the Berglund--H$\ddot{\textnormal{u}}$bsch mirror symmetry. Mase and Ueda \cite{MU} showed that this duality leads to a polytope mirror symmetry of families of $K3$ surfaces. We discuss in this article how this symmetry extends to a symmetry between lattices.

math.AG↗
arXiv2014

A note on bimodal singularities and mirror symmetry

We discuss the relation between transposition mirror symmetry of Berlund and Hübsch for bimodal singularities and polar duality of Batyrev for associated toric K3 hypersurfaces. We also show that homological mirror symmetry for singularities implies the geometric construction of Coxeter-Dynkin diagrams of bimodal singularities by Ebeling and Ploog.

math.AG↗
arXiv2012

A note on exceptional unimodal singularities and K3 surfaces

This is a short note on the relation between the graded stable derived categories of 14 exceptional unimodal singularities and the derived category of K3 surfaces obtained as compactifications of the Milnor fibers. As a corollary, we obtain a basis of the numerical Grothendieck group similar to the one given by Ebeling and Ploog (arXiv:0809.2738).

math.AG↗
arXiv2010

Isomorphism among families of weighted K3 hypersurfaces

Some of the 95 families of weighted K3 hypersurfaces have been known to have the isometric lattice polarizations. It is shown that weighted K3 hypersurfaces in such families are to one-to-one correspond by explicitly constructing the monomial birational morphisms among the weighted projective spaces. All the weight systems having the isometric Picard lattices commonly possess an anticanonical sublinear system, being confirmed that the Picard lattice of the sublinear system we obtained is the same as those of the complete linear systems.

math.AG↗