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Colloquium

RIMS-IMI Colloquium


Title

Lattice and Isogeny Algorithms and Their Applications to Post-Quantum Cryptography

Date

2017.2.1 (Wed) 16:10~17:10    (15:40- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Katsuyuki Takashima (Mitsubishi Electric)

Abstract

Recently, developing post-quantum cryptosystems has been an active research area for preparing emergence (or large deployment) of quantum computers. I will introduce lattice-based and isogeny-based cryptosystems in this talk. Shor's algorithm solves factoring and discrete-logarithm problems in quantum polynomial time. Moreover, the quantum algorithm efficiently solves a wide range of hidden subgroup problems in abelian groups. Therefore, we need mathematical structures, computational assumptions and cryptographic constructions on the structures to avoid the powerful attack. I will survey how to use lattices and isogenies for the purpose.

Comment

Title

Singular fibers of stable maps and their applications

Date

2017.2.1 (Wed) 17:40~18:40    (17:10- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Osamu Saeki (IMI, Kyushu University)

Comment

Title

Stability and bifurcation analysis of the compressible Navier-Stokes equations

Date

2017.1.25 (Wed) 15:00~16:00

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Yoshiyuki Kagei (Kyushu University)

Comment 16:00-16:40 Tea Break (Rm109)

Title

Analytic K-theory of rigid spaces

Date

2017.1.25 (Wed) 16:40~17:40

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Shuji Saito (Tokyo Institute of Technology)

Abstract

[pdf]

Comment 16:00-16:40 Tea Break (Rm109)

Title

Fargues' conjecture on geometrization of the local Langlands correspondence

Date

2017.1.18 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Naoki Imai (The University of Tokyo)

Comment

Title

Rigidity and quasi-invariance for determinantal point processes

Date

2017.1.17 (Tue) 17:00~18:00    (16:30- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Tomoyuki Shirai (IMI, Kyushu University)

Comment

Title

Higher dimensional generalization of Iwasawa theory and related problems

Date

2017.1.11 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Tadashi Ochiai (Osaka University)

Comment

Title

On motivic cohomology with compact support

Date

2016.12.14 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Kanetomo Sato (Chuo University)

Comment

Title

Some recent developments of an $L^2$ extension theorem

Date

2016.12.7 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Takeo Ohsawa (Nagoya University)

Comment

Title

Birational type of orthogonal modular varieties

Date

2016.11.30 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Shohei Ma (Tokyo Institute of Technology)

Comment

Title

The reduction modulo p of crystalline representations and hypergeometric polynomials

Date

2016.11.16 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Go Yamashita (RIMS, Kyoto University)

Comment

Title

A journey into the theory of computable structures

Date

2016.11.9 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Bakhadyr Khoussainov (RIMS & The University of Auckland, Department of Computer Science)

Abstract

In this talk we introduce the concept of computable structure(such as computable group, graph, algebra, partial order, etc.). We present motivation of the subject, discuss its history, and explain topics and questions that have developed the subject over many years. We explain the role of computability, logic, and algebra in the study of various computable structures. The talk will be informal, non-technical, will contain a good amount of examples and explanations, and accessible to a general mathematics and computer science audience.

Comment

Title

Modern Abstract Mathematics at Work: Disentangling Complex Computer Systems with Category Theory and Logic

Date

2016.11.2 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Ichiro Hasuo (The University of Tokyo)

Comment

Title

Models of torsors under elliptic curves

Date

2016.10.26 (Wed) 15:00~16:00    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Kentaro Mitsui (Kobe University)

Abstract

We classify reductions of torsors (principal homogeneous spaces) under elliptic curves over a complete discrete valuation field with perfect residue field. Models of such torsors are analogues of elliptic fibrations over a disk. As an application, we show that there exists a separable closed point of small degree on such a torsor.

Comment

Title

Normalized entropy versus volume for pseudo-Anosovs

Date

2016.10.26 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Sadayoshi Kojima (Tokyo Institute of Technology)

Abstract

We show that the ratio of the normalized entropy of pseudo-Anosovs of surfaces to the volume of their mapping tori is bounded from below by a positive constant not depending on the topology of surfaces, and then discuss a few of its corollaries.

Comment

Title

Recent cryptology and mathematics

Date

2016.10.19 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Koji Nuida (AIST ⁄ JST PRESTO)

Comment

Title

Arithmetics of determinantal representations of plane cubics

Date

2016.10.12 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm127, Building No.3, Faculty of Science, Kyoto University

Speaker

Yasuhiro Ishitsuka (Kyoto University)

Comment

Title

Isothermal two-phase flows with phase transitions

Date

2016.10.5 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Senjo Shimizu (Kyoto University)

Comment

Title

Del Pezzo surfaces and exceptional groups

Date

2016.7.20 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Nicholas Shepherd-Barron (King's College London)

Abstract

The configuration of lines on a del Pezzo surface, such as a cubic surface, leads to various root data, which lead in turn to simple algebraic groups. After reviewing these constructions, we show how to invert the process, by passing in a direct geometrical way from the group to the surface. This inverse construction, which is joint work with Grojnowski, is motivated by boundary phenomena for moduli of K3 surfaces.

Comment

Title

Global instability of solutions for drift-diffusion equations in higher dimensions

Date

2016.7.13 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Takayoshi Ogawa (Tohoku University)

Comment

Title

Motives and heights

Date

2016.7.6 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Teruhisa Koshikawa (RIMS, Kyoto University)

Comment

Title

LOGSPACE vs. PTIME

Date

2016.6.29 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Kazuo Iwama (RIMS, Kyoto University)

Abstract

The famous P vs. NP question asks whether the class of problems that can be solved in polynomial time is different from the class of problems that can be solved in polynomial time if we are given a ``witness''. This super famous open question hides many other open questions about the hierarchy of complexity classes, including the equally important question on the possible difference between logarithmic space and polynomial time. This is the main topic of this talk: Toward the ultimate goal of separating those classes, the problem called the tree evaluation problem was recently introduced. In this talk, we study why this problem is important for our goal and as its first step, we obtain a certain lower bound on its computational complexity using the computation model called branching programs.

Comment

Title

The homotopy type of spaces of resultants and related topics

Date

2016.6.22 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Kohhei Yamaguchi (The University of Electro-Communications)

Abstract

[pdf]

Comment

Title

Applications of algebraic D-modules to projective varieites.

Date

2016.6.15 (Wed) 14:40~15:40

Place

Rm420, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Robin Hartshorne (University of California, Berkeley)

Abstract

[pdf]

Comment 15:40-16:30 Tea Break (Rm110)

Title

Quantum scattering in time-periodic electromagnetic fields

Date

2016.6.15 (Wed) 16:30~17:30

Place

Rm420, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Tadayoshi Adachi (Kyoto University)

Comment 15:40-16:30 Tea Break (Rm110)

Title

Transition to turbulence in subcritical flows: dynamical systems and beyond

Date

2016.6.8 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Paul Manneville 氏 (RIMS & École polytechnique)

Abstract

Understanding the transition to turbulence at a concrete level has great importance both conceptually and practically. Once put in the realm of dynamical systems theory by Ruelle and Takens (1971), the problem can be considered as essentially solved for systems like Rayleigh-Bénard convection experiencing a progressive and continuous, globally supercritical growth of disorder. For open flows, difficulties arise when there is no relevant linear instability mechanism to explain the wilder form of transition to turbulence that then takes place via coexisting domains of laminar and turbulent flow. I will give a brief overview of the situation and discuss the currently developed paths followed to improve our understanding, from the search for exact solutions of the Navier-Stokes equations within dynamical systems theory to tentative modeling in terms of stochastic systems of use in statistical physics.

Comment

Title

Integrated version of Varadhan's asymptotics for first-order perturbations of strong local Dirichlet forms

Date

2016.6.1 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Masanori Hino (Kyoto University)

Comment

Title

Intrinsic Diophantine approximation on homogenous algebraic varieties

Date

2016.5.25 (Wed) 15:00~16:00    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Amos Nevo (Technion)

Abstract

We will describe a recently developed general approach to the problem of intrinsic Diophantine approximation on homogeneous algebraic varieties, raised by Serge Lang in 1965, and demonstrate it in many natural examples. The approach utilizes harmonic analysis in the automorphic representation associated with a lattice in an algebraic group, together with some arguments in homogeneous dynamics and ergodic theory. It provides the best possible solution to some previously inaccessible intrinsic Diophantine approximation problems, and raises some challenging open problems in others.
Based on joint work with Anish Ghosh and Alex Gorodnik.

Comment

Title

Random walks on (hyperbolic) groups

Date

2016.5.25 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Pierre Mathieu (RIMS & Université d'Aix-Marseille)

Abstract

The first part of the talk will be an introduction to the general theory of random walks on groups with some classical results on entropy, rate of escape ... . For hyperbolic groups, these probabilistic objects have geometric counterparts in terms of Gromov boundary, quasi-conformal measures ... I will mention applications and open questions. Finally I will discuss fluctuation results - like the central limit theorem - in particular a recent work with A. Sisto on deviation inequalities for random walks on cylindrically hyperbolic groups.

Comment

Title

On an algebro-geometric realization of the cohomology ring of conical symplectic resolutions

Date

2016.5.11 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Tatsuyuki Hikita (RIMS, Kyoto University)

Comment

Title

On viscous incompressible flows around a rotating obstacle in two-dimensions

Date

2016.4.27 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Building No.3, Faculty of Science, Kyoto University

Speaker

Yasunori Maekawa (Kyoto University)

Comment

Title

Towards criteria for K-stability of Fano manifolds

Date

2016.4.20 (Wed) 16:30~17:30    (16:00- tea)

Place

Rm110, Research Institute for Mathematical Sciences, Kyoto University

Speaker

Kento Fujita (RIMS, Kyoto University)

Comment

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