Text only print
Full screen print
Infinite Analysis Seminar Tokyo
Seminar information archive ～04/25｜Next seminar｜Future seminars 04/26～
| Date, time & place | Saturday 13:30 - 16:00 117Room #117 (Graduate School of Math. Sci. Bldg.) |
|---|
Seminar information archive
2011/10/22
13:30-16:00 Room #117 (Graduate School of Math. Sci. Bldg.)
Leonid Rybnikov (IITP, and State University Higher School of Economics,
Department of Mathematics) 13:30-14:30
Quantization of Quasimaps' Spaces (joint work with M. Finkelberg) (ENGLISH)
Instituteof Biochemical Physics) 15:00-16:00
Quantum integrable models with elliptic R-matrices
and elliptic hypergeometric series (ENGLISH)
Leonid Rybnikov (IITP, and State University Higher School of Economics,
Department of Mathematics) 13:30-14:30
Quantization of Quasimaps' Spaces (joint work with M. Finkelberg) (ENGLISH)
[ Abstract ]
Quasimaps' space Z_d (also known as Drinfeld's Zastava space) is a
remarkable compactification of the space of based degree d maps from
the projective line to the flag variety of type A. The space Z_d has a
natural Poisson structure,
which goes back to Atiyah and Hitchin. We describe
the Quasimaps' space as some quiver variety, and define the
Atiyah-Hitchin Poisson structure in quiver terms.
This gives a natural way to quantize this Poisson structure.
The quantization of the coordinate ring of the Quasimaps' space turns
to be some natural subquotient of the Yangian of type A.
I will also discuss some generalization of this result to the BCD types.
Anton Zabrodin ( Quasimaps' space Z_d (also known as Drinfeld's Zastava space) is a
remarkable compactification of the space of based degree d maps from
the projective line to the flag variety of type A. The space Z_d has a
natural Poisson structure,
which goes back to Atiyah and Hitchin. We describe
the Quasimaps' space as some quiver variety, and define the
Atiyah-Hitchin Poisson structure in quiver terms.
This gives a natural way to quantize this Poisson structure.
The quantization of the coordinate ring of the Quasimaps' space turns
to be some natural subquotient of the Yangian of type A.
I will also discuss some generalization of this result to the BCD types.
Instituteof Biochemical Physics) 15:00-16:00
Quantum integrable models with elliptic R-matrices
and elliptic hypergeometric series (ENGLISH)
[ Abstract ]
Intertwining operators for infinite-dimensional representations of the
Sklyanin algebra with spins l and -l-1 are constructed using the technique of
intertwining vectors for elliptic L-operator. They are expressed in
terms of
elliptic hypergeometric series with operator argument. The intertwining
operators obtained (W-operators) serve as building blocks for the
elliptic R-matrix
which intertwines tensor product of two L-operators taken in
infinite-dimensional
representations of the Sklyanin algebra with arbitrary spin. The
Yang-Baxter equation
for this R-matrix follows from simpler equations of the star-triangle
type for the
W-operators. A natural graphic representation of the objects and
equations involved
in the construction is used.
Intertwining operators for infinite-dimensional representations of the
Sklyanin algebra with spins l and -l-1 are constructed using the technique of
intertwining vectors for elliptic L-operator. They are expressed in
terms of
elliptic hypergeometric series with operator argument. The intertwining
operators obtained (W-operators) serve as building blocks for the
elliptic R-matrix
which intertwines tensor product of two L-operators taken in
infinite-dimensional
representations of the Sklyanin algebra with arbitrary spin. The
Yang-Baxter equation
for this R-matrix follows from simpler equations of the star-triangle
type for the
W-operators. A natural graphic representation of the objects and
equations involved
in the construction is used.
2011/06/02
16:30-17:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Yoshihisa Saito (Graduate School of Mathematical Sciences, Univ. of Tokyo)
On the module category of $¥overline{U}_q(¥mathfrak{sl}_2)$ (JAPANESE)
Yoshihisa Saito (Graduate School of Mathematical Sciences, Univ. of Tokyo)
On the module category of $¥overline{U}_q(¥mathfrak{sl}_2)$ (JAPANESE)
[ Abstract ]
In the representation theory of quantum groups at roots of unity, it is
often assumed that the parameter $q$ is a primitive $n$-th root of unity
where $n$ is a odd prime number. However, there has recently been
increasing interest in the the cases where $n$ is an even integer ---
for example, in the study of logarithmic conformal field theories, or in
knot invariants. In this talk,
we work out a fairly detailed study on the category of finite
dimensional
modules of the restricted quantum $¥overline{U}_q(¥mathfrak{sl}_2)$
where
$q$ is a $2p$-th root of unity, $p¥ge2$.
In the representation theory of quantum groups at roots of unity, it is
often assumed that the parameter $q$ is a primitive $n$-th root of unity
where $n$ is a odd prime number. However, there has recently been
increasing interest in the the cases where $n$ is an even integer ---
for example, in the study of logarithmic conformal field theories, or in
knot invariants. In this talk,
we work out a fairly detailed study on the category of finite
dimensional
modules of the restricted quantum $¥overline{U}_q(¥mathfrak{sl}_2)$
where
$q$ is a $2p$-th root of unity, $p¥ge2$.
2010/09/14
10:30-14:00 Room #117 (Graduate School of Math. Sci. Bldg.)
Shintarou Yanagida (Kobe Univ.) 10:30-11:30
AGT conjectures and recursion formulas (JAPANESE)
Yuji Yamada (Rikkyo Univ.) 13:00-14:00
classification of solutions to the reflection equation associated to
trigonometrical $R$-matrix of Belavin (JAPANESE)
Shintarou Yanagida (Kobe Univ.) 10:30-11:30
AGT conjectures and recursion formulas (JAPANESE)
Yuji Yamada (Rikkyo Univ.) 13:00-14:00
classification of solutions to the reflection equation associated to
trigonometrical $R$-matrix of Belavin (JAPANESE)
2010/09/13
10:30-15:30 Room #117 (Graduate School of Math. Sci. Bldg.)
Masahiro Kasatani (Tokyo Univ.) 10:30-11:30
Polynomial representations of DAHA of type $C^¥vee C$ and boundary qKZ equations (JAPANESE)
CFT, Isomonodromy deformations and Nekrasov functions (JAPANESE)
Twisted de Rham theory---resonances and the non-resonance (JAPANESE)
Masahiro Kasatani (Tokyo Univ.) 10:30-11:30
Polynomial representations of DAHA of type $C^¥vee C$ and boundary qKZ equations (JAPANESE)
[ Abstract ]
First I will review basic facts about
the double affine Hecke algebra of type $C^¥vee C$
and its polynomial representation.
Next I will intrduce a boundary qKZ equation
and construct its solution in terms of the polynomial representation.
Yasuhiko Yamada (Kobe Univ.) 13:00-14:00First I will review basic facts about
the double affine Hecke algebra of type $C^¥vee C$
and its polynomial representation.
Next I will intrduce a boundary qKZ equation
and construct its solution in terms of the polynomial representation.
CFT, Isomonodromy deformations and Nekrasov functions (JAPANESE)
[ Abstract ]
This talk is an introduction to the relation between conformal filed
theories
and super symmetric gauge theories (Alday-Gaiotto-Tachikawa conjecture)
from the point of view of differential equations (in particular
isomonodromy
deformations).
Katsuhisa Mimachi (Tokyo Institute of Technology) 14:30-15:30This talk is an introduction to the relation between conformal filed
theories
and super symmetric gauge theories (Alday-Gaiotto-Tachikawa conjecture)
from the point of view of differential equations (in particular
isomonodromy
deformations).
Twisted de Rham theory---resonances and the non-resonance (JAPANESE)
2010/09/12
10:30-17:00 Room #117 (Graduate School of Math. Sci. Bldg.)
Hideaki Morita (Muroran Institute of Technology) 10:30-11:30
A factorization formula for Macdonald polynomials at roots of unity (JAPANESE)
W algebras and symmetric polynomials (JAPANESE)
Quantizing the difference Painlev¥'e VI equation (JAPANESE)
On a bijective proof of a factorization formula for Macdonald
polynomials at roots of unity (JAPANESE)
Hideaki Morita (Muroran Institute of Technology) 10:30-11:30
A factorization formula for Macdonald polynomials at roots of unity (JAPANESE)
[ Abstract ]
We consider a combinatorial property of Macdonald polynomials at roots
of unity.
If we made some plethystic substitution to the variables,
Macdonald polynomials are subjected to a certain decomposition rule
when a parameter is specialized at roots of unity.
We review the result and give an outline of the proof.
This talk is based on a joint work with F. Descouens.
Junichi Shiraishi (Tokyo Univ.) 13:00-14:00We consider a combinatorial property of Macdonald polynomials at roots
of unity.
If we made some plethystic substitution to the variables,
Macdonald polynomials are subjected to a certain decomposition rule
when a parameter is specialized at roots of unity.
We review the result and give an outline of the proof.
This talk is based on a joint work with F. Descouens.
W algebras and symmetric polynomials (JAPANESE)
[ Abstract ]
It is well known that we have the factorization property of the Macdonald polynomials under the principal specialization $x=(1,t,t^2,t^3,¥cdots)$. We try to better understand this situation in terms of the Ding-Iohara algebra or the deformend $W$-algebra. Some conjectures are presented in the case of $N$-fold tensor representation of the Fock modules.
Koji Hasegawa (Tohoku Univ.) 14:30-15:30It is well known that we have the factorization property of the Macdonald polynomials under the principal specialization $x=(1,t,t^2,t^3,¥cdots)$. We try to better understand this situation in terms of the Ding-Iohara algebra or the deformend $W$-algebra. Some conjectures are presented in the case of $N$-fold tensor representation of the Fock modules.
Quantizing the difference Painlev¥'e VI equation (JAPANESE)
[ Abstract ]
I will review two constructions for quantum (=non-commutative) version of
q-difference Painleve VI equation.
Yasuhide Numata (Graduate School of Information Science and Technology, Tokyo Univ.) 16:00-17:00I will review two constructions for quantum (=non-commutative) version of
q-difference Painleve VI equation.
On a bijective proof of a factorization formula for Macdonald
polynomials at roots of unity (JAPANESE)
[ Abstract ]
The subject of this talk is a factorization formula for the special
values of modied Macdonald polynomials at roots of unity.
We give a combinatorial proof of the formula, via a result by
Haglund--Haiman--Leohr, for some special classes of partitions,
including two column partitions.
(This talk is based on a joint work with F. Descouens and H. Morita.)
The subject of this talk is a factorization formula for the special
values of modied Macdonald polynomials at roots of unity.
We give a combinatorial proof of the formula, via a result by
Haglund--Haiman--Leohr, for some special classes of partitions,
including two column partitions.
(This talk is based on a joint work with F. Descouens and H. Morita.)
2010/09/11
13:00-17:00 Room #117 (Graduate School of Math. Sci. Bldg.)
Masahiko Ito (School of Science and Technology for Future Life, Tokyo Denki University) 13:00-14:00
Three-term recurrence relations for a $BC_n$-type basic hypergeometric function and their application (JAPANESE)
TBA (JAPANESE)
Masato Taki (YITP Kyoto Univ.) 16:00-17:00
AGT conjecture and geometric engineering (JAPANESE)
Masahiko Ito (School of Science and Technology for Future Life, Tokyo Denki University) 13:00-14:00
Three-term recurrence relations for a $BC_n$-type basic hypergeometric function and their application (JAPANESE)
[ Abstract ]
$BC_n$-type basic hypergeometric series are a certain $q$-analogue
of an integral representation for the Gauss hypergeometric function.
They are defined as multiple $q$-series satisfying Weyl group symmetry of type $C_n$,
and they are a multi-sum generalization of the basic hypergeometric series
in a class of what is called (very-)well-poised. In my talk I will explain
an explicit expression for the $q$-difference system of rank $n+1$
satisfied by a $BC_n$-type basic hypergeometric series with 6+1 parameters
as first order simultaneous $q$-difference equations with a concrete basis.
For this purpose I introduce two types of symmetric Laurent polynomials
which I call the $BC$-type interpolation polynomials. The polynomials satisfy
three-term relations like a contiguous relation for the Gauss hypergeometric
function. As an application, I will show another proof for the product formula
of the $q$-integral introduced by Gustafson.
Masatoshi Noumi (Kobe Univ.) 14:30-15:30$BC_n$-type basic hypergeometric series are a certain $q$-analogue
of an integral representation for the Gauss hypergeometric function.
They are defined as multiple $q$-series satisfying Weyl group symmetry of type $C_n$,
and they are a multi-sum generalization of the basic hypergeometric series
in a class of what is called (very-)well-poised. In my talk I will explain
an explicit expression for the $q$-difference system of rank $n+1$
satisfied by a $BC_n$-type basic hypergeometric series with 6+1 parameters
as first order simultaneous $q$-difference equations with a concrete basis.
For this purpose I introduce two types of symmetric Laurent polynomials
which I call the $BC$-type interpolation polynomials. The polynomials satisfy
three-term relations like a contiguous relation for the Gauss hypergeometric
function. As an application, I will show another proof for the product formula
of the $q$-integral introduced by Gustafson.
TBA (JAPANESE)
Masato Taki (YITP Kyoto Univ.) 16:00-17:00
AGT conjecture and geometric engineering (JAPANESE)
2009/12/22
10:00-14:00 Room #056 (Graduate School of Math. Sci. Bldg.)
岩尾 慎介 (東大数理) 10:00-11:00
離散周期KP方程式の簡約と、初期値問題の解の構成
Laplacian on graphs: Examples from physics
岩尾 慎介 (東大数理) 10:00-11:00
離散周期KP方程式の簡約と、初期値問題の解の構成
[ Abstract ]
様々に簡約された離散周期KP方程式に対して、スペクトル曲線を用いた逆散乱解法を考える。 このとき、簡約の種類によっては、超楕円とは限らない代数曲線が多数あらわれてくる。 本講演では、簡約周期KP方程式の初期値問題の解を構成する方法を紹介する。この方法はFayの恒等式を用いない構成的なもので、わかりやすいものである。
Y. Avishai (Ben Gurion University) 13:00-14:00様々に簡約された離散周期KP方程式に対して、スペクトル曲線を用いた逆散乱解法を考える。 このとき、簡約の種類によっては、超楕円とは限らない代数曲線が多数あらわれてくる。 本講演では、簡約周期KP方程式の初期値問題の解を構成する方法を紹介する。この方法はFayの恒等式を用いない構成的なもので、わかりやすいものである。
Laplacian on graphs: Examples from physics
[ Abstract ]
When the Laplacian operator is written as a second order difference operator the physicists refer to it as a tight-binding model. In two dimensions the eigenvalue problem connects the function at a given point to the sum of its values on its nearest neighbors. In numerous physical problems, some of the coefficients are multiplied by phase factors. This problem is amazingly rich and the pattern of eigenvalues E(φ) has a fractal nature known as the Hofstadter butterfly.
I will discuss some of these models and especially concentrate on two problems, which I solved recently, where the vertices of the graphs are located on the sphere S2. The first one corresponds to the famous problem of the Dirac magnetic monopole, while in the second one, the eigenfunctions are two component vectors and the phase factors are replaced by unitary 2x2 matrices. This is relevant to the spin-orbit problem in Physics. In both cases the solutions can be obtained in closed form, and exhibit a beautiful symmetry pattern. Their elucidation requires some special techniques in graph theory. Quite surprisingly, the spectra of the two systems coincide at one symmetry point.
When the Laplacian operator is written as a second order difference operator the physicists refer to it as a tight-binding model. In two dimensions the eigenvalue problem connects the function at a given point to the sum of its values on its nearest neighbors. In numerous physical problems, some of the coefficients are multiplied by phase factors. This problem is amazingly rich and the pattern of eigenvalues E(φ) has a fractal nature known as the Hofstadter butterfly.
I will discuss some of these models and especially concentrate on two problems, which I solved recently, where the vertices of the graphs are located on the sphere S2. The first one corresponds to the famous problem of the Dirac magnetic monopole, while in the second one, the eigenfunctions are two component vectors and the phase factors are replaced by unitary 2x2 matrices. This is relevant to the spin-orbit problem in Physics. In both cases the solutions can be obtained in closed form, and exhibit a beautiful symmetry pattern. Their elucidation requires some special techniques in graph theory. Quite surprisingly, the spectra of the two systems coincide at one symmetry point.
2009/11/07
13:30-16:00 Room #117 (Graduate School of Math. Sci. Bldg.)
Andrei Marshakov (Lebedev Physical Institute) 13:30-14:30
Tau-functions of Toda theories, partitions and conformal blocks
TBA
Andrei Marshakov (Lebedev Physical Institute) 13:30-14:30
Tau-functions of Toda theories, partitions and conformal blocks
[ Abstract ]
I discuss the class of tau-functions,
corresponding to special solutions of integrable systems,
related to Hurwitz numbers and supersymmetric Yang-Mills
theories. Their natural generalization turn to coincide with
the conformal blocks of two-dimensional conformal
field theories. In special case these conformal
blocks turn into the scalar products of certain ``coherent
states'' in the highest-weight module of the Virasoro
algebra, generalizing the matrix elements
for the well-known coherent states in Fock spaces.
TBA (TBA) 15:00-16:00I discuss the class of tau-functions,
corresponding to special solutions of integrable systems,
related to Hurwitz numbers and supersymmetric Yang-Mills
theories. Their natural generalization turn to coincide with
the conformal blocks of two-dimensional conformal
field theories. In special case these conformal
blocks turn into the scalar products of certain ``coherent
states'' in the highest-weight module of the Virasoro
algebra, generalizing the matrix elements
for the well-known coherent states in Fock spaces.
TBA
[ Abstract ]
TBA
TBA
2009/07/24
13:00-15:30 Room #056 (Graduate School of Math. Sci. Bldg.)
武部尚志 (Faculty of Math, Higher School of Economics, Moscow) 13:00-14:00
On recursion relation of the KP hierarchy
球面のフルビッツ数とKP・戸田階層の特殊解
武部尚志 (Faculty of Math, Higher School of Economics, Moscow) 13:00-14:00
On recursion relation of the KP hierarchy
[ Abstract ]
This talk is based on an ongoing project in collaboration with Takasaki and Tsuchiya. Our goal is to reconstruct and generalise results by Eynard et al. from the standpoint of the integrable systems. Eynard, Orantin and their collaborators found "topological recursion formulae" to describe partition functions and correlation functions of the matrix models, topological string theories etc., using simple algebro-geometric data called "spectral curves". On the other hand, it is well known that the partition functions of those theories are tau functions of integrable hierarchies.
We have found that any solution of the KP hierarchy (with an asymptotic expansion parameter h) can be recovered by recursion relations from its "dispersionless" part (which corresponds to the genus zero part in topological theories) and a quantised contact transformation (which corresponds to the string equations) specifying the solution.
高崎金久 (京大人間) 14:30-15:30This talk is based on an ongoing project in collaboration with Takasaki and Tsuchiya. Our goal is to reconstruct and generalise results by Eynard et al. from the standpoint of the integrable systems. Eynard, Orantin and their collaborators found "topological recursion formulae" to describe partition functions and correlation functions of the matrix models, topological string theories etc., using simple algebro-geometric data called "spectral curves". On the other hand, it is well known that the partition functions of those theories are tau functions of integrable hierarchies.
We have found that any solution of the KP hierarchy (with an asymptotic expansion parameter h) can be recovered by recursion relations from its "dispersionless" part (which corresponds to the genus zero part in topological theories) and a quantised contact transformation (which corresponds to the string equations) specifying the solution.
球面のフルビッツ数とKP・戸田階層の特殊解
[ Abstract ]
球面の1点を指定し、その上方で任意被覆型の分岐点
をもち、それ以外では単純分岐点のみもつような n 次分岐被覆を考える。
このような分岐被覆の位相的同型類の個数は単純フルビッツ数と呼ばれる。
1点の代わりに2点を指定して同様に定義されるものは2重フルビッツ数である。
これらのフルビッツ数にシューア函数を乗じて総和したものはそれぞれ
KP階層および戸田階層のτ函数になることが知られている。この講演では
これらの特殊解においてラックス作用素とオルロフ・シュルマン作用素が
満たす関係式 (拘束条件) を紹介し、そこから導かれる帰結を探る。
球面の1点を指定し、その上方で任意被覆型の分岐点
をもち、それ以外では単純分岐点のみもつような n 次分岐被覆を考える。
このような分岐被覆の位相的同型類の個数は単純フルビッツ数と呼ばれる。
1点の代わりに2点を指定して同様に定義されるものは2重フルビッツ数である。
これらのフルビッツ数にシューア函数を乗じて総和したものはそれぞれ
KP階層および戸田階層のτ函数になることが知られている。この講演では
これらの特殊解においてラックス作用素とオルロフ・シュルマン作用素が
満たす関係式 (拘束条件) を紹介し、そこから導かれる帰結を探る。
2009/06/20
11:00-12:00 Room #117 (Graduate School of Math. Sci. Bldg.)
有田親史 (九大数理)
多成分排他過程の固有値が満たす双対性
有田親史 (九大数理)
多成分排他過程の固有値が満たす双対性
[ Abstract ]
非対称単純排他過程(asymmetric simple exclusion process, ASEP)と呼ばれ
る1次元格子上の確率過程がある。今回はその多成分の場合を考える。系の時間
発展を特徴付けるジェネレータ行列(マルコフ行列)は,Heisenberg模型を含む
Perk-Schultz模型のハミルトニアンの特殊な場合と等価である。講演者らは各粒
子セクターを超立方体の頂点と対応させ固有値の構造を調べた。超立方体上で双
対点を成す2つのセクターの固有値が満たす関係を示した。国場敦夫氏,堺和光
氏,沢辺剛氏との共同研究。
非対称単純排他過程(asymmetric simple exclusion process, ASEP)と呼ばれ
る1次元格子上の確率過程がある。今回はその多成分の場合を考える。系の時間
発展を特徴付けるジェネレータ行列(マルコフ行列)は,Heisenberg模型を含む
Perk-Schultz模型のハミルトニアンの特殊な場合と等価である。講演者らは各粒
子セクターを超立方体の頂点と対応させ固有値の構造を調べた。超立方体上で双
対点を成す2つのセクターの固有値が満たす関係を示した。国場敦夫氏,堺和光
氏,沢辺剛氏との共同研究。
2009/04/18
11:00-14:30 Room #117 (Graduate School of Math. Sci. Bldg.)
Vladimir Dobrev (Institute for Nuclear Reserch and Nuclear Energy, Sofia, Bulgaria) 11:00-12:00
Invariant Differential Operators for Non-Compact Lie Groups
TBA
Vladimir Dobrev (Institute for Nuclear Reserch and Nuclear Energy, Sofia, Bulgaria) 11:00-12:00
Invariant Differential Operators for Non-Compact Lie Groups
[ Abstract ]
We present a canonical procedure for the explicit construction of
invariant differential operators. The exposition is for semi-simple
Lie algebras, but is easily generalized to the supersymmetric and
quantum group settings. Especially important is a narrow class of
algebras, which we call 'conformal Lie algebras', which have very
similar properties to the conformal algebras of n-dimensional
Minkowski space-time. Examples are given in detail, including diagrams of
intertwining operators, or equivalently, multiplets of elementary
representations (generalized Verma modules).
笠谷昌弘 (東大数理) 13:30-14:30We present a canonical procedure for the explicit construction of
invariant differential operators. The exposition is for semi-simple
Lie algebras, but is easily generalized to the supersymmetric and
quantum group settings. Especially important is a narrow class of
algebras, which we call 'conformal Lie algebras', which have very
similar properties to the conformal algebras of n-dimensional
Minkowski space-time. Examples are given in detail, including diagrams of
intertwining operators, or equivalently, multiplets of elementary
representations (generalized Verma modules).
TBA
[ Abstract ]
TBA
TBA
2009/03/21
11:00-14:30 Room #117 (Graduate School of Math. Sci. Bldg.)
梶原 康史 (神戸理) 11:00-12:00
On classes of transformations for bilinear sum of
(basic) hypergeometric series and multivariate generalizations.
On explicit formulas for Whittaker functions on real semisimple Lie groups
梶原 康史 (神戸理) 11:00-12:00
On classes of transformations for bilinear sum of
(basic) hypergeometric series and multivariate generalizations.
[ Abstract ]
In this talk, I will present classes of bilinear transformation
formulas for basic hypergeometric series and Milne's multivariate
basic hypergeometric series associated with the root system of
type $A$. Our construction is similar to one of elementary
proof of Sears-Whipple transformation formula for terminating
balanced ${}_4 \\phi_3$ series while we use multiple Euler
transformation formula with different dimensions which has
obtained in our previous work.
石井 卓 (成蹊大理工) 13:30-14:30In this talk, I will present classes of bilinear transformation
formulas for basic hypergeometric series and Milne's multivariate
basic hypergeometric series associated with the root system of
type $A$. Our construction is similar to one of elementary
proof of Sears-Whipple transformation formula for terminating
balanced ${}_4 \\phi_3$ series while we use multiple Euler
transformation formula with different dimensions which has
obtained in our previous work.
On explicit formulas for Whittaker functions on real semisimple Lie groups
[ Abstract ]
will report explicit formulas
for Whittaker functions related to principal series
reprensetations on real semisimple Lie groups $G$ of
classical type.
Our explicit formulas are recursive formulas with
respect to the real rank of $G$, and in some lower rank
cases they are related to generalized
hypergeometric series $ {}_3F_2(1) $ and $ {}_4F_3(1) $.
will report explicit formulas
for Whittaker functions related to principal series
reprensetations on real semisimple Lie groups $G$ of
classical type.
Our explicit formulas are recursive formulas with
respect to the real rank of $G$, and in some lower rank
cases they are related to generalized
hypergeometric series $ {}_3F_2(1) $ and $ {}_4F_3(1) $.
2009/02/14
10:30-14:00 Room #117 (Graduate School of Math. Sci. Bldg.)
藤健太 (神戸理) 10:30-11:30
野海・山田系におけるタウ関数の関係式
ワイル群の regular な共役類に付随するドリンフェルト・ソコロフ階層とパンルヴェ型微分方程式
藤健太 (神戸理) 10:30-11:30
野海・山田系におけるタウ関数の関係式
[ Abstract ]
野海・山田系は, A型のドリンフェルト・ソコロフ階層の相似簡約から得られる高階
の常微分方程式系である.
本講演では, ドリンフェルト・ソコロフ階層を波動作用素を用いて考察することによっ
て, 野海・山田系のタウ関数の双線形方程式を求める.
鈴木貴雄 (神戸理) 13:00-14:00野海・山田系は, A型のドリンフェルト・ソコロフ階層の相似簡約から得られる高階
の常微分方程式系である.
本講演では, ドリンフェルト・ソコロフ階層を波動作用素を用いて考察することによっ
て, 野海・山田系のタウ関数の双線形方程式を求める.
ワイル群の regular な共役類に付随するドリンフェルト・ソコロフ階層とパンルヴェ型微分方程式
[ Abstract ]
ドリンフェルト・ソコロフ階層はKdV階層のアフィン・リー代数への一般化で, ワイ
ル群の共役類(またはハイゼンベルグ部分代数)によって特徴付けられる可積分系で
ある.
本講演では, ワイル群の共役類のうち特に regular と呼ばれるものに注目し, それ
に対応するドリンフェルト・ソコロフ階層の定式化について, F.Kroode-J.Leur, Kik
uchi-Ikeda-Kakei 等の仕事を紹介しつつ解説する.
また, パンルヴェ型微分方程式との関連についても述べる.
ドリンフェルト・ソコロフ階層はKdV階層のアフィン・リー代数への一般化で, ワイ
ル群の共役類(またはハイゼンベルグ部分代数)によって特徴付けられる可積分系で
ある.
本講演では, ワイル群の共役類のうち特に regular と呼ばれるものに注目し, それ
に対応するドリンフェルト・ソコロフ階層の定式化について, F.Kroode-J.Leur, Kik
uchi-Ikeda-Kakei 等の仕事を紹介しつつ解説する.
また, パンルヴェ型微分方程式との関連についても述べる.
2009/01/24
11:00-16:00 Room #117 (Graduate School of Math. Sci. Bldg.)
仲田 研登 (京大数研) 11:00-12:00
一般化されたヤング図形の q-Hook formula
Catalan numbers and level 2 weight structures of $A^{(1)}_{p-1}$
On a dimer model with impurities
仲田 研登 (京大数研) 11:00-12:00
一般化されたヤング図形の q-Hook formula
[ Abstract ]
Young図形における hook formula は、組合せ論的には、その Young 図形の standar
d tableau の総数を数え上げる公式である。R. P. Stanley は reverse plane parti
tion のなす母関数を考えることにより、この公式をq-hook formula に拡張し、E. R
. Gansner はそれをさらに多変数に一般化した。
本講演では、この(多変数)q-Hook formula が(D. Peterson、R. A. Proctor の意
味の)一般化されたYoung図形においても成り立つこと紹介する。特にこれはPeterso
n の hook formula の証明も与える。
土岡 俊介 (京大数研) 13:30-14:30Young図形における hook formula は、組合せ論的には、その Young 図形の standar
d tableau の総数を数え上げる公式である。R. P. Stanley は reverse plane parti
tion のなす母関数を考えることにより、この公式をq-hook formula に拡張し、E. R
. Gansner はそれをさらに多変数に一般化した。
本講演では、この(多変数)q-Hook formula が(D. Peterson、R. A. Proctor の意
味の)一般化されたYoung図形においても成り立つこと紹介する。特にこれはPeterso
n の hook formula の証明も与える。
Catalan numbers and level 2 weight structures of $A^{(1)}_{p-1}$
[ Abstract ]
Motivated by a connection between representation theory of
the degenerate affine Hecke algebra of type A and
Lie theory associated with $A^{(1)}_{p-1}$, we determine the complete
set of representatives of the orbits for the Weyl group action on
the set of weights of level 2 integrable highest weight representations of $\\widehat{\\mathfrak{sl}}_p$.
Applying a crystal technique, we show that Catalan numbers appear in their weight multiplicities.
Here "a crystal technique" means a result based on a joint work with S.Ariki and V.Kreiman,
which (as an application of the Littelmann's path model) combinatorially characterize
the connected component (usually called Kleshchev bipartition in the representation theoretic context)
$B(\\Lambda_0+\\Lambda_s)\\subseteq B(\\Lambda_0)\\otimes B(\\Lambda_s)$ in the tensor product.
中野 史彦 (高知大理学部数学) 15:00-16:00Motivated by a connection between representation theory of
the degenerate affine Hecke algebra of type A and
Lie theory associated with $A^{(1)}_{p-1}$, we determine the complete
set of representatives of the orbits for the Weyl group action on
the set of weights of level 2 integrable highest weight representations of $\\widehat{\\mathfrak{sl}}_p$.
Applying a crystal technique, we show that Catalan numbers appear in their weight multiplicities.
Here "a crystal technique" means a result based on a joint work with S.Ariki and V.Kreiman,
which (as an application of the Littelmann's path model) combinatorially characterize
the connected component (usually called Kleshchev bipartition in the representation theoretic context)
$B(\\Lambda_0+\\Lambda_s)\\subseteq B(\\Lambda_0)\\otimes B(\\Lambda_s)$ in the tensor product.
On a dimer model with impurities
[ Abstract ]
We consider the dimer problem on a non-bipartite graph $G$, where there are two types of dimers one of which we regard impurities. Results of simulations using Markov chain seem to indicate that impurities are tend to distribute on the boundary, which we set as a conjecture. We first show that there is a bijection between the set of dimer coverings on
$G$ and the set of spanning forests on two graphs which are made from $G$, with configuration of impurities satisfying a pairing condition, and this bijection can be regarded as a extension of the Temperley bijection. We consider local move consisting of two operations, and by using the bijection mentioned above, we prove local move connectedness. Finally, we prove that the above conjecture is true,
in some spacial cases.
We consider the dimer problem on a non-bipartite graph $G$, where there are two types of dimers one of which we regard impurities. Results of simulations using Markov chain seem to indicate that impurities are tend to distribute on the boundary, which we set as a conjecture. We first show that there is a bijection between the set of dimer coverings on
$G$ and the set of spanning forests on two graphs which are made from $G$, with configuration of impurities satisfying a pairing condition, and this bijection can be regarded as a extension of the Temperley bijection. We consider local move consisting of two operations, and by using the bijection mentioned above, we prove local move connectedness. Finally, we prove that the above conjecture is true,
in some spacial cases.
2008/11/22
13:30-16:00 Room #117 (Graduate School of Math. Sci. Bldg.)
桂 法称 ((理化学研究所)
理化学研究所) 13:30-14:30
Quantum Entanglement in Exactly Solvable Models
非例外型KRクリスタルについて
桂 法称 ((理化学研究所)
理化学研究所) 13:30-14:30
Quantum Entanglement in Exactly Solvable Models
[ Abstract ]
近年、量子情報論的な観点からの量子多体問題の研究が盛んに行われている。
特に基底状態におけるentanglementのvon Neumann(entanglement) entropyなどの
指標を用いた特徴づけが盛んに議論されている。これらの研究において可解模型
は、この新しく導入された指標が量子多体系の基本性質を正しく反映しているか
をテストする一種の実験室として重要な役割を果たしてきた。セミナーでは、
先ずentanglement entropyの定義などについての簡単な説明を行い、その後私が
主に行ってきた以下の幾つかのテーマについてご紹介したい。
1. Affleck-Kennedy-Lieb-Tasaki modelのvalence bond solid基底状態におけるenta
nglementと端状態
2. Calogero-Sutherland modelにおける粒子間entanglementと排他的分数統計
3. Bethe ansatz波動関数の行列積表示
尚、本研究は初田泰之(東大理), 平野嵩明(東大工)、丸山勲(大阪大)、初貝安弘(筑
波大)、Ying Xu, Vladimir E. Korepin(SUNY at Stony Brook)各氏との共同研究に基
づくものである。
尾角正人 (阪大基礎工) 15:00-16:00近年、量子情報論的な観点からの量子多体問題の研究が盛んに行われている。
特に基底状態におけるentanglementのvon Neumann(entanglement) entropyなどの
指標を用いた特徴づけが盛んに議論されている。これらの研究において可解模型
は、この新しく導入された指標が量子多体系の基本性質を正しく反映しているか
をテストする一種の実験室として重要な役割を果たしてきた。セミナーでは、
先ずentanglement entropyの定義などについての簡単な説明を行い、その後私が
主に行ってきた以下の幾つかのテーマについてご紹介したい。
1. Affleck-Kennedy-Lieb-Tasaki modelのvalence bond solid基底状態におけるenta
nglementと端状態
2. Calogero-Sutherland modelにおける粒子間entanglementと排他的分数統計
3. Bethe ansatz波動関数の行列積表示
尚、本研究は初田泰之(東大理), 平野嵩明(東大工)、丸山勲(大阪大)、初貝安弘(筑
波大)、Ying Xu, Vladimir E. Korepin(SUNY at Stony Brook)各氏との共同研究に基
づくものである。
非例外型KRクリスタルについて
[ Abstract ]
KRクリスタルとはアフィンリー環gのディンキン図の0以外の頂点と
正整数に付随して定義される量子アフィン代数の特殊な有限次元
表現(KR加群)の結晶基底である。KRクリスタルの存在は非例外型
の場合には昨年確認された。今年になって、それらの結晶グラフの
構造が組合せ論的に具体的にわかる進展があったので、そのこと
についてgが$A_{2n-1}^{(2)}$と$C_n^{(1)}$の場合にお話したい。
また、組合せ論的に与えた結晶グラフが、なぜ表現論的に存在が
わかった結晶基底のグラフと一致するかについての証明の概略に
ついても触れたい。
KRクリスタルとはアフィンリー環gのディンキン図の0以外の頂点と
正整数に付随して定義される量子アフィン代数の特殊な有限次元
表現(KR加群)の結晶基底である。KRクリスタルの存在は非例外型
の場合には昨年確認された。今年になって、それらの結晶グラフの
構造が組合せ論的に具体的にわかる進展があったので、そのこと
についてgが$A_{2n-1}^{(2)}$と$C_n^{(1)}$の場合にお話したい。
また、組合せ論的に与えた結晶グラフが、なぜ表現論的に存在が
わかった結晶基底のグラフと一致するかについての証明の概略に
ついても触れたい。
2008/07/26
13:30-16:00 Room #117 (Graduate School of Math. Sci. Bldg.)
星野歩 (上智大理) 13:30-14:30
変形W代数とMacdomald多項式のtableau表示
Entanglement Entropy in Conventional and Topological Orders
星野歩 (上智大理) 13:30-14:30
変形W代数とMacdomald多項式のtableau表示
[ Abstract ]
A型変形W代数の自由場表示を用いてA型Macdomald多項式のtableau表示を構成する。さらにD型変形W代数の自由場表示を用いて、第一基本ウェイトの正数倍のウェイトを持つD型Macdomald多項式のtableau表示を構成する。尚、本研究は白石潤一氏(東京大学)との共同研究である。
古川俊輔 (理化学研究所) 15:00-16:00A型変形W代数の自由場表示を用いてA型Macdomald多項式のtableau表示を構成する。さらにD型変形W代数の自由場表示を用いて、第一基本ウェイトの正数倍のウェイトを持つD型Macdomald多項式のtableau表示を構成する。尚、本研究は白石潤一氏(東京大学)との共同研究である。
Entanglement Entropy in Conventional and Topological Orders
[ Abstract ]
量子多体系の基底状態には、しばしば、個々の粒子の状態の直積では表せない構造、すなわち、エンタングルメントが現れる。これを、エンタングルメント・エントロピーという指標を用いて測ることにより、系のユニヴァーサリティを特徴づける重要な情報が得られることが近年、明らかにされてきた。セミナーでは、エンタングルメントについての基礎的な知識から始め、私が取り組んできた(いる)、次の二つのテーマについてご紹介したい。
(1)量子ダイマー模型におけるトポロジカル・エントロピー
トポロジカル秩序を持つ系においては、エンタングルメント・エントロピーに、背景のゲージ理論を特徴づける、負の定数項が含まれることが、Kitaevらによって予想された。我々は、Z2トポロジカル秩序を示すと考えられる量子ダイマー模型において、予想の数値的検証を行い、予想が精度よく成り立つことを示した。
Ref. S. Furukawa & G. Misguich, Phys. Rev. B 75, 214407 (2007).
(2)自発的対称性の破れとマクロスコピック・エンタングルメント
自発的対称性の破れを示す系においては、有限系の基底状態に、秩序を持った状態のマクロな重ね合わせ構造が見られる。この構造がエンタングルメント・エントロピーにも反映され、基底状態縮退度の情報を含む、正の定数項が現れることを示した。
量子多体系の基底状態には、しばしば、個々の粒子の状態の直積では表せない構造、すなわち、エンタングルメントが現れる。これを、エンタングルメント・エントロピーという指標を用いて測ることにより、系のユニヴァーサリティを特徴づける重要な情報が得られることが近年、明らかにされてきた。セミナーでは、エンタングルメントについての基礎的な知識から始め、私が取り組んできた(いる)、次の二つのテーマについてご紹介したい。
(1)量子ダイマー模型におけるトポロジカル・エントロピー
トポロジカル秩序を持つ系においては、エンタングルメント・エントロピーに、背景のゲージ理論を特徴づける、負の定数項が含まれることが、Kitaevらによって予想された。我々は、Z2トポロジカル秩序を示すと考えられる量子ダイマー模型において、予想の数値的検証を行い、予想が精度よく成り立つことを示した。
Ref. S. Furukawa & G. Misguich, Phys. Rev. B 75, 214407 (2007).
(2)自発的対称性の破れとマクロスコピック・エンタングルメント
自発的対称性の破れを示す系においては、有限系の基底状態に、秩序を持った状態のマクロな重ね合わせ構造が見られる。この構造がエンタングルメント・エントロピーにも反映され、基底状態縮退度の情報を含む、正の定数項が現れることを示した。
2008/06/14
13:30-16:00 Room #117 (Graduate School of Math. Sci. Bldg.)
孫 娟娟 (東大数理) 13:30-14:30
Confluent KZ equations for $sl_2$ and quantization of monodromy preserving deformation
Exact Solution and Physical Combinatorics of Critical Dense
Polymers
孫 娟娟 (東大数理) 13:30-14:30
Confluent KZ equations for $sl_2$ and quantization of monodromy preserving deformation
[ Abstract ]
We obtain a system of confluent Knizhnik-Zamolodchikov (KZ) equations which generalizes that of KZ equations for $sl_2$,
and give integral solutions of the system. We also study the relation between the system and monodromy preserving deformation theory,
and recover quantizations of Painlev\\'e equations P_I-P_V with affine Weyl group symmetry which are introduced by H.Nagoya.
Paul A. Pearce (Univ. of Melbourne) 15:00-16:00We obtain a system of confluent Knizhnik-Zamolodchikov (KZ) equations which generalizes that of KZ equations for $sl_2$,
and give integral solutions of the system. We also study the relation between the system and monodromy preserving deformation theory,
and recover quantizations of Painlev\\'e equations P_I-P_V with affine Weyl group symmetry which are introduced by H.Nagoya.
Exact Solution and Physical Combinatorics of Critical Dense
Polymers
[ Abstract ]
A Yang-Baxter integrable model of critical dense polymers on the
square lattice
is introduced corresponding to the first member ${\\cal LM}(1,2)$ of a
family of logarithmic
minimal models. The model has no local degrees of freedom, only non-
local degrees
of freedom in the form of extended polymers. The model is built
diagrammatically using the
planar Temperley-Lieb algebra and solved exactly on finite width
strips using transfer matrix
techniques. The bulk and boundary free energies and finite-size
corrections are
obtained from the Euler-Maclaurin formula. The spectra are classified
by selection rules and
the physical combinatorics of the eigenvalue patterns of zeros in the
complex
spectral-parameter plane. This yields explicit finitized conformal
characters.
In particular, in the scaling limit, we confirm the central charge
$c=-2$ and conformal weights
$\\Delta_{1,s}=\\frac{(2-s)^2-1}{8}$ for $s=1,2,3,\\ldots$ where $s-1$ is
the number
of defects.
A Yang-Baxter integrable model of critical dense polymers on the
square lattice
is introduced corresponding to the first member ${\\cal LM}(1,2)$ of a
family of logarithmic
minimal models. The model has no local degrees of freedom, only non-
local degrees
of freedom in the form of extended polymers. The model is built
diagrammatically using the
planar Temperley-Lieb algebra and solved exactly on finite width
strips using transfer matrix
techniques. The bulk and boundary free energies and finite-size
corrections are
obtained from the Euler-Maclaurin formula. The spectra are classified
by selection rules and
the physical combinatorics of the eigenvalue patterns of zeros in the
complex
spectral-parameter plane. This yields explicit finitized conformal
characters.
In particular, in the scaling limit, we confirm the central charge
$c=-2$ and conformal weights
$\\Delta_{1,s}=\\frac{(2-s)^2-1}{8}$ for $s=1,2,3,\\ldots$ where $s-1$ is
the number
of defects.
2008/02/23
13:00-16:30 Room #270 (Graduate School of Math. Sci. Bldg.)
岩尾慎介 (東大数理) 13:00-14:30
Solutions of hungry periodic discrete Toda equation and its ultradiscretization
A tropical analogue of Fay's trisecant identity and its application to the ultra-discrete periodic Toda equation.
岩尾慎介 (東大数理) 13:00-14:30
Solutions of hungry periodic discrete Toda equation and its ultradiscretization
[ Abstract ]
The hungry discrete Toda equation is a generalization of the discrete Toda
equation. Through the method of ultradiscretization, the generalized
Box-ball system (gBBS) with finitely many kinds of balls is obtained from
hungry discrete Toda eq.. It is to be expected that the general solution of
gBBS should be obtained from the solution of hungry discrete Toda eq.
through ultradiscretization. In this talk, we derive the solutions of hungry
periodic discrete Toda eq. (hpd Toda eq.), by using inverse scattering
method. Although the hpd Toda equation does not linearlized in the usual
sense on the Picard group of the spectral curve, it is possible to determine
its behavior on the Picard group.
竹縄知之 (東京海洋大・海洋工) 15:00-16:30The hungry discrete Toda equation is a generalization of the discrete Toda
equation. Through the method of ultradiscretization, the generalized
Box-ball system (gBBS) with finitely many kinds of balls is obtained from
hungry discrete Toda eq.. It is to be expected that the general solution of
gBBS should be obtained from the solution of hungry discrete Toda eq.
through ultradiscretization. In this talk, we derive the solutions of hungry
periodic discrete Toda eq. (hpd Toda eq.), by using inverse scattering
method. Although the hpd Toda equation does not linearlized in the usual
sense on the Picard group of the spectral curve, it is possible to determine
its behavior on the Picard group.
A tropical analogue of Fay's trisecant identity and its application to the ultra-discrete periodic Toda equation.
[ Abstract ]
The ultra-discrete Toda equation is essentially equivalent to the integrable
Box and Ball system, and considered to be a fundamental object in
ultra-discrete integrable systems. In this talk, we construct the general
solution of ultra-discrete Toda equation with periodic boundary condition,
by using the tropical theta function and the bilinear form. The tropical
theta function is associated with the tropical curve defined through the Lax
matrix of (not ultra-) discrete periodic Toda equation. For the proof, we
introduce a tropical analogue of Fay's trisecant identity. (This talk is
based on the joint work with R. Inoue.)
The ultra-discrete Toda equation is essentially equivalent to the integrable
Box and Ball system, and considered to be a fundamental object in
ultra-discrete integrable systems. In this talk, we construct the general
solution of ultra-discrete Toda equation with periodic boundary condition,
by using the tropical theta function and the bilinear form. The tropical
theta function is associated with the tropical curve defined through the Lax
matrix of (not ultra-) discrete periodic Toda equation. For the proof, we
introduce a tropical analogue of Fay's trisecant identity. (This talk is
based on the joint work with R. Inoue.)
2007/12/22
13:00-16:30 Room #117 (Graduate School of Math. Sci. Bldg.)
池田岳 (岡山理大理) 13:00-14:30
Double Schubert polynomials for the classical Lie groups
Nichols-Woronowicz model of the K-ring of flag vaieties G/B
池田岳 (岡山理大理) 13:00-14:30
Double Schubert polynomials for the classical Lie groups
[ Abstract ]
For each infinite series of the classical Lie groups of type $B$,
$C$ or $D$, we introduce a family of polynomials parametrized by the
elements of the corresponding Weyl group of infinite rank. These
polynomials
represent the Schubert classes in the equivariant cohomology of the
corresponding
flag variety. When indexed by maximal Grassmannian elements of the Weyl
group,
these polynomials are equal to the factorial analogues of Schur $Q$- or
$P$-functions defined earlier by Ivanov. This talk is based on joint work
with L. Mihalcea and H. Naruse.
前野 俊昭 (京大工) 15:00-16:30For each infinite series of the classical Lie groups of type $B$,
$C$ or $D$, we introduce a family of polynomials parametrized by the
elements of the corresponding Weyl group of infinite rank. These
polynomials
represent the Schubert classes in the equivariant cohomology of the
corresponding
flag variety. When indexed by maximal Grassmannian elements of the Weyl
group,
these polynomials are equal to the factorial analogues of Schur $Q$- or
$P$-functions defined earlier by Ivanov. This talk is based on joint work
with L. Mihalcea and H. Naruse.
Nichols-Woronowicz model of the K-ring of flag vaieties G/B
[ Abstract ]
We give a model of the equivariant $K$-ring $K_T(G/B)$ for
generalized flag varieties $G/B$ in the braided Hopf algebra
called Nichols-Woronowicz algebra. Our model is based on
the Chevalley-type formula for $K_T(G/B)$ due to Lenart
and Postnikov, which is described in terms of alcove paths.
We also discuss a conjecture on the model of the quantum
$K$-ring $QK(G/B)$.
We give a model of the equivariant $K$-ring $K_T(G/B)$ for
generalized flag varieties $G/B$ in the braided Hopf algebra
called Nichols-Woronowicz algebra. Our model is based on
the Chevalley-type formula for $K_T(G/B)$ due to Lenart
and Postnikov, which is described in terms of alcove paths.
We also discuss a conjecture on the model of the quantum
$K$-ring $QK(G/B)$.
2007/11/17
13:00-16:30 Room #126 (Graduate School of Math. Sci. Bldg.)
Gleb Novichkov (Keio Univ.) 13:00-14:30
Dynamical r-matrices coupled with dual Poisson Lie group
Yang-Baxter Equation and Quantum Geometry
Gleb Novichkov (Keio Univ.) 13:00-14:30
Dynamical r-matrices coupled with dual Poisson Lie group
[ Abstract ]
The notion dynamical r-matrix coupled with Poisson manifold
is a natural generalization of the notion of the classical
dynamical r-matrix. We will consider special case when
Poisson manifold is a dual Poisson Lie group. We discuss
necessary conditions for the existence dynamical r-matrices
coupled with dual Poisson Lie groups and provide
some examples. We will also discuss some open questions
and possible relations to other subjects.
Vladimir V. Bazhanov (Australian National Univ.) 15:00-16:30The notion dynamical r-matrix coupled with Poisson manifold
is a natural generalization of the notion of the classical
dynamical r-matrix. We will consider special case when
Poisson manifold is a dual Poisson Lie group. We discuss
necessary conditions for the existence dynamical r-matrices
coupled with dual Poisson Lie groups and provide
some examples. We will also discuss some open questions
and possible relations to other subjects.
Yang-Baxter Equation and Quantum Geometry
[ Abstract ]
We demonstrate that certain integrable models
of statistical mechanics and quantum field theory
can be interpreted as quantization's of objects
of classical discrete geometry.
The fluctuating variables in these models take continuous
values. The classical geometry corresponds to stationary
configurations in the quasi-classical (or zero-temperature)
limit of the quantum system.
Our main example is the Faddeev-Volkov model which describes
the quantization of the circle patterns and associated with
the Thurston's discrete analogue of the Riemann mapping theorem
(discrete conformal transformations of the 2D plane).
Other examples will be also considered.
Finally we will discuss the geometric origins of integrability
which stem from from the classical results of Lam\\'e,
Darboux and Bianchi in differential geometry.
We demonstrate that certain integrable models
of statistical mechanics and quantum field theory
can be interpreted as quantization's of objects
of classical discrete geometry.
The fluctuating variables in these models take continuous
values. The classical geometry corresponds to stationary
configurations in the quasi-classical (or zero-temperature)
limit of the quantum system.
Our main example is the Faddeev-Volkov model which describes
the quantization of the circle patterns and associated with
the Thurston's discrete analogue of the Riemann mapping theorem
(discrete conformal transformations of the 2D plane).
Other examples will be also considered.
Finally we will discuss the geometric origins of integrability
which stem from from the classical results of Lam\\'e,
Darboux and Bianchi in differential geometry.
2007/06/16
13:30-16:00 Room #117 (Graduate School of Math. Sci. Bldg.)
土岡俊介 (京都大学数理解析研究所) 13:30-14:30
Lie theoretic structures for the generalized symmetric groups
Wirtinger 積分の構造について
土岡俊介 (京都大学数理解析研究所) 13:30-14:30
Lie theoretic structures for the generalized symmetric groups
[ Abstract ]
近年、Ariki, Brundan, Grojnowski, Kleshchev, Vazirani等によって、
modular表現論とKac-Moody Lie環/量子群といったLie theoreticな対象との関係が研究
されて来た。このうち対称群のmodular表現論については、
(1) 標数p>0において、対称群\\mathfrak{S}_nの(有限次元)表現のGrothendieck群の
(nを走らせた)直和には、Kac-Moody Lie環g(A^{1}_{p-1})のレベル1基本既約最高
weight表現の構造を入れることが出来る。
(2) 対称群の既約表現の同型類の直和には、量子群U_q(g(A^{1}_{p-1}))の
レベル1基本既約最高weight表現に付随する(Kashiwaraの意味での)結晶構造を
入れることが出来る。
と、その関係をまとめることが出来る。
講演者は以前、複素鏡映群(あるいは一般化対称群)G(m,1,n)のmodular分岐則の
研究において、(A^{(1)}_{p-1})^{\\otimes r}(ここでrはpとmから決まる自然数)
に付随する量子群との関係を示唆する結果を得たので、まずはそれを解説したい。
次に、G(m,1,n)における(1),(2)の対応物の構成する現在進行中の試みについて、
当日までに出来ているところを解説する予定である。
なお、G(m,1,n)の群環のq-変形と考えられているcyclotomic Hecke algebraにおいて、
qが1でない1の羃根の場合は既に(1),(2)の対応物が知られているので、時間が許せば
それとの比較についても解説したい。
渡辺文彦 (北見工業大学) 15:00-16:00近年、Ariki, Brundan, Grojnowski, Kleshchev, Vazirani等によって、
modular表現論とKac-Moody Lie環/量子群といったLie theoreticな対象との関係が研究
されて来た。このうち対称群のmodular表現論については、
(1) 標数p>0において、対称群\\mathfrak{S}_nの(有限次元)表現のGrothendieck群の
(nを走らせた)直和には、Kac-Moody Lie環g(A^{1}_{p-1})のレベル1基本既約最高
weight表現の構造を入れることが出来る。
(2) 対称群の既約表現の同型類の直和には、量子群U_q(g(A^{1}_{p-1}))の
レベル1基本既約最高weight表現に付随する(Kashiwaraの意味での)結晶構造を
入れることが出来る。
と、その関係をまとめることが出来る。
講演者は以前、複素鏡映群(あるいは一般化対称群)G(m,1,n)のmodular分岐則の
研究において、(A^{(1)}_{p-1})^{\\otimes r}(ここでrはpとmから決まる自然数)
に付随する量子群との関係を示唆する結果を得たので、まずはそれを解説したい。
次に、G(m,1,n)における(1),(2)の対応物の構成する現在進行中の試みについて、
当日までに出来ているところを解説する予定である。
なお、G(m,1,n)の群環のq-変形と考えられているcyclotomic Hecke algebraにおいて、
qが1でない1の羃根の場合は既に(1),(2)の対応物が知られているので、時間が許せば
それとの比較についても解説したい。
Wirtinger 積分の構造について
[ Abstract ]
Wirtinger はガウスの超幾何函数 $_2F_1$ を一意化する目的でこれを
テータ函数の冪積の積分で表わす表示を1902年に得た.Wirtinger の発見以降,
この積分に関する組織的な研究は講演者の調べた限りではほとんど無いのであるが,
この積分を講演者は前述に因んで Wirtinger 積分と呼んでいる.
この積分は実質的には超幾何函数なのであるが,あえてこの事実を忘れテータ函数の
公式のみを用いて Wirtinger 積分のみたすさまざまな関係式を導出することが
できれば,それはテータ函数論の観点からのガウスの超幾何函数論の再構成と
見做すことができる.
実際,講演者はこの立場から超幾何函数の接続行列やモノドロミー行列,微分方程式の
再導出を最近おこなった.また,講演者がこの積分に注目しているもうひとつの
理由は,超幾何函数の新しい一般化の可能性が Wirtinger 積分に見えているという
ことである.
本講演では Wirtinger 積分と超幾何函数との関係および一般化の可能性について,
講演者のおこなった方法および得た結果を中心に,妄想を交えつつ解説する.
数学のスタイルは古典解析的である(真古典解析ではないが新古典的か).
小生は世間の情報にうといので,講演中などにWirtinger 積分の関連で
何らかの情報をご教示いただければ幸いです.
Wirtinger はガウスの超幾何函数 $_2F_1$ を一意化する目的でこれを
テータ函数の冪積の積分で表わす表示を1902年に得た.Wirtinger の発見以降,
この積分に関する組織的な研究は講演者の調べた限りではほとんど無いのであるが,
この積分を講演者は前述に因んで Wirtinger 積分と呼んでいる.
この積分は実質的には超幾何函数なのであるが,あえてこの事実を忘れテータ函数の
公式のみを用いて Wirtinger 積分のみたすさまざまな関係式を導出することが
できれば,それはテータ函数論の観点からのガウスの超幾何函数論の再構成と
見做すことができる.
実際,講演者はこの立場から超幾何函数の接続行列やモノドロミー行列,微分方程式の
再導出を最近おこなった.また,講演者がこの積分に注目しているもうひとつの
理由は,超幾何函数の新しい一般化の可能性が Wirtinger 積分に見えているという
ことである.
本講演では Wirtinger 積分と超幾何函数との関係および一般化の可能性について,
講演者のおこなった方法および得た結果を中心に,妄想を交えつつ解説する.
数学のスタイルは古典解析的である(真古典解析ではないが新古典的か).
小生は世間の情報にうといので,講演中などにWirtinger 積分の関連で
何らかの情報をご教示いただければ幸いです.
2007/05/26
13:00-16:30 Room #117 (Graduate School of Math. Sci. Bldg.)
酒井一博 (慶応大経済) 13:00-14:30
弦理論対応における可積分性
AdS/CFT 対応における $a$-maximization について
酒井一博 (慶応大経済) 13:00-14:30
弦理論対応における可積分性
[ Abstract ]
概要:N=4超対称ゲージ理論と反ド・ジッター時空を背景とする弦理論の等価性を主
張するAdS/CFT対応は、ここ十年弦理論の分野でもっとも活発に研究されてい
るテーマのひとつである。この枠組の中で、伝統的な一次元量子可積分系や二
次元古典可積分系と同種の可積分構造が発見され、近年飛躍的な研究の進展が
続いている。この流れは、既存の可積分系の知識の単なる応用にとどまらず、
一次元Hubbard模型の可積分性の背景にある代数構造を明らかにするなど、可
積分系の分野へのフィードバックをももたらしている。本講演では、ゲージ理
論・弦理論双方で可積分性がどのように現れるかを概観しながら、この分野の
研究の最前線を紹介する。
加藤晃史 (東大数理) 15:00-16:30概要:N=4超対称ゲージ理論と反ド・ジッター時空を背景とする弦理論の等価性を主
張するAdS/CFT対応は、ここ十年弦理論の分野でもっとも活発に研究されてい
るテーマのひとつである。この枠組の中で、伝統的な一次元量子可積分系や二
次元古典可積分系と同種の可積分構造が発見され、近年飛躍的な研究の進展が
続いている。この流れは、既存の可積分系の知識の単なる応用にとどまらず、
一次元Hubbard模型の可積分性の背景にある代数構造を明らかにするなど、可
積分系の分野へのフィードバックをももたらしている。本講演では、ゲージ理
論・弦理論双方で可積分性がどのように現れるかを概観しながら、この分野の
研究の最前線を紹介する。
AdS/CFT 対応における $a$-maximization について
[ Abstract ]
弦双対性の一つである AdS/CFT 対応において、$a$-maximization
と呼ばれる変分問題が4次元超対称共形場理論のスペクトルの決定に
重要な働きをするがわかってきた。本講演では非専門家向けに
$a$-maximization の基本的な構造を説明するとともに、
関連するいくつかの話題を紹介したい。
弦双対性の一つである AdS/CFT 対応において、$a$-maximization
と呼ばれる変分問題が4次元超対称共形場理論のスペクトルの決定に
重要な働きをするがわかってきた。本講演では非専門家向けに
$a$-maximization の基本的な構造を説明するとともに、
関連するいくつかの話題を紹介したい。
2007/04/14
13:00-16:30 Room #117 (Graduate School of Math. Sci. Bldg.)
長尾健太郎 (京大理) 13:00-14:30
q-Fock空間と非対称Macdonald多項式
The Quantum Knizhnik-Zamolodchikov Equation
and Non-symmetric Macdonald Polynomials
長尾健太郎 (京大理) 13:00-14:30
q-Fock空間と非対称Macdonald多項式
[ Abstract ]
斎藤-竹村-Uglov,Varagnolo-Vasserotによって,q-Fock空間に
A型量子トロイダル代数のレベル(0,1)表現の構造が入ることが知られています.
この表現をある可換部分代数に制限して得られる作用の同時固有ベクトルを,
非対称Macdonald多項式を用いて構成することができます.
さらにこの同時固有ベクトルをq-Fock空間の基底とすることで,
量子トロイダル代数の作用を組合せ論的に記述することができます.
今回のセミナーでは,斎藤-竹村-Uglov,Varagnolo-Vasserotの構成を
振り返ったあとで,同時固有ベクトルの構成法を紹介します.
最後に箙多様体の同変K群との関連について少しだけ言及します.
笠谷昌弘 (京大理) 15:00-16:30斎藤-竹村-Uglov,Varagnolo-Vasserotによって,q-Fock空間に
A型量子トロイダル代数のレベル(0,1)表現の構造が入ることが知られています.
この表現をある可換部分代数に制限して得られる作用の同時固有ベクトルを,
非対称Macdonald多項式を用いて構成することができます.
さらにこの同時固有ベクトルをq-Fock空間の基底とすることで,
量子トロイダル代数の作用を組合せ論的に記述することができます.
今回のセミナーでは,斎藤-竹村-Uglov,Varagnolo-Vasserotの構成を
振り返ったあとで,同時固有ベクトルの構成法を紹介します.
最後に箙多様体の同変K群との関連について少しだけ言及します.
The Quantum Knizhnik-Zamolodchikov Equation
and Non-symmetric Macdonald Polynomials
[ Abstract ]
We construct special solutions of the quantum Knizhnik-Zamolodchikov equation
on the tensor product of the vector representation of
the quantum algebra of type $A_{N-1}$.
They are constructed from non-symmetric Macdonald polynomials
through the action of the affine Hecke algebra.
As special cases,
(i) the matrix element of the vertex operators
of level one is reproduced, and
(ii) we give solutions of level $\\frac{N+1}{N}-N$.
(ii) is a generalization of the solution of
level $-\\frac{1}{2}$ by V.Pasquier and me.
This is a jount work with Y.Takeyama.
We construct special solutions of the quantum Knizhnik-Zamolodchikov equation
on the tensor product of the vector representation of
the quantum algebra of type $A_{N-1}$.
They are constructed from non-symmetric Macdonald polynomials
through the action of the affine Hecke algebra.
As special cases,
(i) the matrix element of the vertex operators
of level one is reproduced, and
(ii) we give solutions of level $\\frac{N+1}{N}-N$.
(ii) is a generalization of the solution of
level $-\\frac{1}{2}$ by V.Pasquier and me.
This is a jount work with Y.Takeyama.
2007/03/17
13:30-14:30 Room #117 (Graduate School of Math. Sci. Bldg.)
Paul Wiegmann (Chicago Univ.)
Calogero model and Quantum Benjamin-Ono Equation
Paul Wiegmann (Chicago Univ.)
Calogero model and Quantum Benjamin-Ono Equation
[ Abstract ]
TBA
TBA
2007/02/17
13:30-16:00 Room #117 (Graduate School of Math. Sci. Bldg.)
阿部 友紀 (上智理工数学) 13:30-14:30
Finite-dimensional representations of the small quantum algebras
Combinatorics of Young walls and crystal bases
阿部 友紀 (上智理工数学) 13:30-14:30
Finite-dimensional representations of the small quantum algebras
[ Abstract ]
量子代数は定義にパラメーターを一つ含み、量子代数の表現論は、
そのパラメーターが1のべき根であるか、そうでないかによって大きく異なる。
さらに、1のべき根の場合は、Lusztig氏によって定義された「制限型量子代数」と、
De Conini-Kac氏らによって定義された「非制限型量子代数」の2種類が存在し、
それぞれ表現論が異なる。
また、制限型量子代数は、「小型量子代数(=small quantum algebra)」と
呼ばれる真部分代数を含み、その表現論は、制限型量子代数と非制限型量子代数の
どちらの表現論においても重要な役割を果たしている。
今回の講演では、主に以下の3点について説明したい:
●小型量子代数が、非制限型量子代数のある商代数と同型になることを、
有限型とループ型の場合に示す。
●A, B, C, D, G型の小型量子代数の有限次元既約表現を、
Schnizer表現の部分表現として構成する。
●A型の小型ループ量子代数のevaluation表現の性質を調べる。
Seok-Jin Kang (Seoul National University) 15:00-16:00量子代数は定義にパラメーターを一つ含み、量子代数の表現論は、
そのパラメーターが1のべき根であるか、そうでないかによって大きく異なる。
さらに、1のべき根の場合は、Lusztig氏によって定義された「制限型量子代数」と、
De Conini-Kac氏らによって定義された「非制限型量子代数」の2種類が存在し、
それぞれ表現論が異なる。
また、制限型量子代数は、「小型量子代数(=small quantum algebra)」と
呼ばれる真部分代数を含み、その表現論は、制限型量子代数と非制限型量子代数の
どちらの表現論においても重要な役割を果たしている。
今回の講演では、主に以下の3点について説明したい:
●小型量子代数が、非制限型量子代数のある商代数と同型になることを、
有限型とループ型の場合に示す。
●A, B, C, D, G型の小型量子代数の有限次元既約表現を、
Schnizer表現の部分表現として構成する。
●A型の小型ループ量子代数のevaluation表現の性質を調べる。
Combinatorics of Young walls and crystal bases
[ Abstract ]
We introduce combinatorics of Young walls and give a realization of crystal bases in terms of reduced Young walls. We also discuss their connection with representation theory of Hecke algebras.
We introduce combinatorics of Young walls and give a realization of crystal bases in terms of reduced Young walls. We also discuss their connection with representation theory of Hecke algebras.
