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Susumu Tanabe

Publications and source records attributed to Susumu Tanabe.

8 recordsLinked to original sources
arXiv2024

Braid monodromy for a trinomial algebraic equation by means of Mellin-Barnes integral representations

We establish a braid monodromy representation of functions satisfying an algebraic equation containing three terms (trinomial equation). We follow global analytic continuation of the roots to a trinomial algebraic equation that are expressed by Mellin-Barnes integral representations. We depict braids that arise from the monodromy around all branching points. The global braid monodromy is described in terms of rational twists of strands that yield a classical Artin braid representation of algebraic functions. As a corollary, we get a precise description of the Galois group of a trinomial algebraic equation.

math.AG↗
arXiv2022

Period integrals associated to an affine Delsarte type hypersurface

We calculate the period integrals for a special class of affine hypersurfaces (deformed Delsarte hypersurfaces) in an algebraic torus by the aid of their Mellin transforms. A description of the relation between poles of Mellin transforms of period integrals and the mixed Hodge structure of the cohomology of the hypersurface is given. By interpreting the period integrals as solutions to Pochhammer hypergeometric differential equation, we calculate concretely the irreducible monodromy group of period integrals that correspond to the compactification of the affine hypersurface in a complete simplicial toric variety. As an application of the equivalence between oscillating integral for Delsarte polynomial and quantum cohomology of a weighted projective space $\mathbb{P}_{\bf B}$, we establish an equality between its Stokes matrix and the Gram matrix of the full exceptional collection on $\mathbb{P}_{\bf B}$.

math.AG↗
arXiv2020

Brieskorn module and Center conditions: pull-back of differential equations in projective space

The moduli space of algebraic foliations on P2 of a fixed degree and with a center singularity has many irreducible components. We find a basis of the Brieskorn module defined for a rational function and prove that set of pull-back foliations forms an irreducible component of the moduli space. The main tools are the Picard-Lefschetz theory of a rational function in two variables, period integrals, and the Brieskorn module.

math.DS↗
arXiv2010

Wave fronts and (almost) free divisors

In this note we present a description of wave front evolving from an algebraic hypersurface by means of a pull-back of the discriminantal loci of a tame polynomial via a polynomial mapping. As an application we give examples of wave fronts which define free/almost free divisors near the focal point.

math.AG↗
arXiv2006

Transposition mirror symmetry construction and period integrals

In this note we study several conditions to be imposed on a mirror symmetry candidate to the generic multi-quasihomogeneous Calabi-Yau variety defined in the product of the quasihomogeneous projective spaces. We propose several properties for a Calabi-Yau complete intersection variety so that its period integrals can be expressed by means of quasihomogeneous weights of its mirror symmetry candidate as it has been suggested by Berglund, Candelas et altri. As a corollary, we see certain duality between the monodromy data and the Poincaré polynomials of the Euler characteristic for the pairs of our varieties.

math.AG↗
arXiv2004

Systeme des coordonees plates de la deformation verselle des singularites isolees simples d'hypersurface et zeros de l'integrale d'Abel

One studies a system of differential equations defined by Abel integrals associated to a real cycle defined for the versal deformation of an isolated simple singularity. As application, one obtains an estimation on the multiplicity of zeros of the Abel integral in terms of quasihomogeneous weights associated to the Hamiltonian and the integrand function.

math.DS↗