seminar

Studio Phones Seminar

We extended this seminar at Kobe Univerity

Studio Phones Seminar at Kobe University(academic, new)

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Upcoming talks

Past seminars

2011/08/23 AM1030-AM1130 / StudioPhones Room301B

"On ring theoretic invariants of quasi-isometry"/ Hokuto Morishima (Osaka University)

abstract

We consider a certain ring for a finitely generated group, and

introduce the results about correspondence of the ring and the

quasi-isometric geometry of the finitely generated group.

2011/08/23 PM0100-PM0200 / StudioPhones Room301B

"On pre-computable category" / Yusuke Kiriu (Studio Phones)

joint with A.Ushijima (Kanazawa University)

abstract

This talk is a brief survey of pre-computable category,

especially, for topological objects, invariant functions,

and algebraic structures.

On the background of our research, we are studying

computer sciences, logics and linguistics. I also talk about

some details of pre-computable category within the context of

2 and 3 dimensional computer graphics and general graphics.

2011/08/23 PM0210-PM0600 / StudioPhones Room301B

"Introduction to Schubert calculus"/ Shizuo Kaji (Yamaguchi University)

abstract

"How many lines are there in the three space which meet all

the four given lines ?"

In 19th century, H.Schubert considered this problem in an insightful but

not rigorous way.

He invented a symbolic "calculation'' for the conditions on lines as follows:

[intersecting a given line]^{\cap 4} = [lying on a given line] \cup

[lying on a given line], and obtained the answer two.

In fact, the "algebra'' of the conditions on lines is isomorphic to the

ring of the symmetric polynomials called Schur polynomials.

D.Hilbert asked for a rigorous foundation for the above calculus as the

15th problem in his 1900 lecture and now Schubert’s quiz can be rephrased in terms of

cohomology, or equivalently, intersection theory of a Grassmaniann manifold.

In this talk, I will briefly review the basics of Schubert calculus with a

focus on the correspondence of several algebras occurring in this subject

including the above one.

2011/03/08 PM0300-PM0600 / StudioPhones Room301B

"Vertex operator algebras and characters of their modules"/ Yusuke Arike (Osaka University)

abstract

I will explain about Zhu's modular invariance property of characters of modules

for rational vertex operator algebras.

2010/07/29 PM0100-PM0500 / StudioPhones Room301B

On the tetrahedral number of hyperbolic manifolds of bounded volume / Yo'av Rieck (University of Arkansas)

after Jorgensen and Thurston, joint with Tsuyoshi Kobayashi

abstract

In the 70's, Jorgensen and Thruston proved that for any V>0 there

exists a finite collection of manifolds X_1,...,X_n so that any

complete hyperbolic 3-manifold of volume at most V is obtained by

filling some X_i. A well-know "folk theorem" of Thruston says that

there exists a constant K so that X_i can be triangulated using at

most KV tetrahedra.

We will first motivate this theorem by describing two applications.

The purpose of this talk is providing a proof of Thurston's theorem.

The proof follows an outline that appeared in the litrature, but as

remarked by Benedetti and Petronio, it requirs control over the

intersection between the Voronoi cells and the thin and thick parts of

the manifolds (the terms will be explained in the talk). We will show

how we control these intersections.

Most of the work is elementary and done in hyperbolic 3-space. I will

make an effort to make it accessible to students familiar with the

upper half space model.

2010/06/4 - 6/27

"Workshop(s): Lefschetz fibration and category theory"

Workshop(s): Lefschetz fibration and category theory

2010/03/15 PM0100-PM0500 / StudioPhones Room301B

"On a variation of the Gordian complex" In Dae Jong (Osaka City University)

abstract

This is a joint work with Kazuhiro Ichihara.

We will introduce simplicial complexes by using various invariants and

local moves on knots, which give generalizations of the Gordian complex

defined by Hirasawa and Uchida.

In this talk, we will study simplicial complexes defined by using the

Alexander-Conway polynomial and the crossing change or the Delta-move.

We will show that these simplicial complexes are Gromov hyperbolic.

2010/02/22, 2010/02/23

Workshop : Arithmetic Kleinian group

https://sites.google.com/site/yusukekiriu/home/osaka_arith

2010/02/17 PM0100-PM0300 / StudioPhones Room301B

"On roots of Dehn twists "Naoyuki Monden (Osaka University)

abstract

Margalit and Schleimer constructed nontrivial roots of the

Dehn twist about a nonseparating curve.We prove that the

conjugacy classes of roots of the Dehn twist about a

nonseparating curve correspond to the conjugacy classes

of periodic maps with certain conditions.Furthermore,

we give data set which determine the conjugacy class of a root.

As a consequence, we can find the minimum degree and the

maximum degree, and show that the degree must be odd.

Also, we give Dehn twist expression of the root of degree 3

2010/02/17 PM0300-PM0630 / StudioPhones Room301B

"Handle decompositions of knot complements" Tsubasa Ichikawa (Osaka University)

abstract

Every smooth compact n-manifold is decomposed into some

copies of n-disks (= handles) according to certain rules.

I would like to introduce handle decompositions of manifolds

(especially knot complements) and demonstrate how to draw them.

2010/02/13 AM1000-AM1130 / StudioPhones Room301B

"Quandles and related topics" Yuichi Kabaya (Osaka City University Advanced Mathematical Institute (OCAMI))

abstract

Quandle is an algebraic structure which was introduced by

David Joyce in 1982, motivated by knot theory and conjugation

of a group.In this talk I will introduce several aspects of

quandles and related topics; quandle homology and relation

with group homology, rack space, (twisted) Alexander polynomial, etc.

2010/02/13 PM0100-PM0530 / StudioPhones Room301B

"Iwasawa theory and characteristic invariants" Kazuma Shimomoto

Joint with T.Ochiai (Osaka University)

abstract

In recent years, several people have suggested the various kinds of

Iwasawa Main Conjecture formulated in the language used in their

own field of study.

In this talk, I begin with a brief review on classical Iwasawa theory,

including the classical Main Conjecture. Then I move on to the

p-adic modular forms, L-functions, and the Main Conjecture.

The main theme of this talk is to discuss Bertini-type theorem and

characteristic invariants which also serve as strategic tools

to study similar invariants in toplogy and algebra.

2010/02/10 AM0930-AM1130 / StudioPhones Room301B

"Application of Length of Quandle 3-Cocycle to Surface-Knot Theory" Shin Satoh (Kobe University)

abstract

The homology and cohomology theory of a quandle is useful to

study knotted surfaces in 4-space. We define the length of a

3-cocycle of a quandle equipped with a quandle-set, and calculate

the lengths of some 3-cocycles. We give lower bounds of the triple

point number of a surface-knot by the length of a quandle 3-cocycle.

2010/02/10 PM0100-PM0530 / StudioPhones Room301B

"On quandle homology groups of Alexander quandles of prime order" Takefumi Nosaka (RIMS, Kyoto University)

abstract

Our result is to determine all quandle homology groups of Alexander

quandle of prime order. The proof is obtained from the calculations of

quandle 'co'homology group with the generators (cocycles) by means

of calculus over positive characteristic, which is inspired by

T.Mochizuki's computations of third degree cocycles.

This talk outlines the proof, and our goal is to illustate why 'the

higher degree cocycles are constructed from lower degree ones,

and linear independently generate the quandle cohomology group'.

2009/12/30 AM1000-PM0100 / StudioPhones Room301B

"Similarity between Alexander-Fox Theory and Iwasawa Theory" Teruhisa Kadokami (Dalian University of technology)

abstract

I explain about similarity between Alexander-Fox Theory from

Knot Theory, and Iwasawa Theory from Number Theory.

2009/12/30 PM0230-PM0430 / StudioPhones Room301B

"On F-coherent rings" Kazuma Shimomoto

abstract

I will talk about a new class of Noetherian rings defined by the

Frobenius map and discuss its basic properties.

The talk will also focus on some open questions.

2009/12/30 PM0430-PM0530 / StudioPhones Room301B

"Bertini type theorem and Iwasawa Main Conjecture" Kazuma Shimomoto

Joint with T.Ochiai (Osaka University)

abstract

Iwasawa Main Conjecture (IMC) in two variables was

proposed by several people and proved by K.Rubin in the classical case.

More recently, T.Ochiai formulated IMC over some type of deformation

spaces and he proved it in the case when the deformation space is the

Iwasawa algebra.His idea is to take sufficiently many hypersurfaces

and analyze the problem on them.I will talk about the so-called Bertini

type theorem to generalize IMC to more general deformation spaces.

2009/12/05 AM1000-PM0600 / 2nd Floor, Lecture Room, Kanazawa University Satellite Plaza

"Godel's incompleteness theorem and its application" Shunsuke Yatabe (National Institute of Advanced Industrial Science and Technology)

abstract

In this talk, we introduce an overview of a proof of Godel's

incompleteness theorem. First we see the details of arithmetization of

natural number theory, then we see how Godel sentence is constructed.

Then we see the arithmetical hierarchy and its "circular structure" in

Global sense.

If we have enough time, we also try to see some facts about non-standard

model of Arithmetic.

2009/10/08 PM0100-PM0600 / StudioPhones Room301B

"An Application of Category Theory to Systems Biology" Taichi Haruna (Kobe University/JST)

abstract

We propose a new data analytical tool for directed networks by

using category theory.

We develop a category theoretical treatment of directed networks in

order to obtain functional networks for real networks.

By applying our method to concrete data on real information

processing biological networks, we find a distinguishing global

structure of functional networks.

We discuss a possibility of a new hypothesis on network motifs based on

our theory and data analysis.

We also present a glimpse of calculations when our method is thought of

an abstract graph transformation.

2009/10/30 AM1000-PM0600 / Hiroshima University

小研究集会;Symbolic description and low-dimensional topology

基盤研究B

「3次元多様体のヘガード構造と幾何構造 」

研究課題番号：18340018

代表者：作間誠

により支援を受けています

2009/10/16~18 AM0900-PM0600 / Shinshu University

Workshop : Category Theory , Computer Science and Topology

学長裁量経費 (教育・研究経費)

「数理科学分野の連携と融合，創成：信州数理科学特別重点研究」

研究代表者: 井上和行

により部分的に支援を受けています

pre-workshop seminar

2009/10/14 AM1000-AM1200 / StudioPhones Room301B

"Cohen-Macaulay modules over Gorenstein rings" Tokuji Araya (Nara University of Education)

abstract

Gorenstein rings have nice homological properties to investigate the

category of finitely generated modules.

In this talk, I will give some basic properties of Cohen-Macaulay modules

over Gorenstein rings.

2009/10/14 PM0100-PM0500 / StudioPhones Room301B

"Cohen-Macaulay modules over Gorenstein rings" Tokuji Araya (Nara University of Education)

abstract

Gorenstein rings have nice homological properties to investigate the

category of finitely generated modules.

In this talk, I will give some basic properties of Cohen-Macaulay modules

over Gorenstein rings.

2009/ 9/27 AM1000-PM0100 / StudioPhones Room301B

"Basics of plane curves" Hisanori Ohashi (RIMS, Kyoto University)

abstract

I will give an introduction to algebraic geometry. We will see several aspects of

algebraic curves, being as conscious to the general theory as possible.

If time permits, I will explain the Mathieu group, the first generation

of the Happy Family of finite simple sporadic groups.

2009/ 9/27 PM0200-PM0400 / StudioPhones Room301B

"Geometry of second order PDE" Kazuhiro Shibuya (Hiroshima University)

abstract

This is an introduction to exterior differential systems.

I will talk the classical theory given by E.Cartan.

2009/ 9/27 PM0400-PM0600 / StudioPhones Room301B

"Symbolic Manipulation for pure functions" Yusuke Kiriu (Studio Phones)

(Joint with T.Sakasai)

-Mathematica pure functions as being like Lambda expressions or anonymous functions-

abstract