Colloquia & Seminars Archives - Page 122 of 129

Seminars: Colloquia & Seminars

Date
Time
Venue

Speaker
Affiliation
Title of Talk

02 May 2019
16:00
S17 #06-11

Zhang Shuangjian
École Nationale de la Statistique et de l'Administration Économique, Paris, France
On concavity of the principal’s profit maximization facing agents who respond nonliearly to prices

On concavity of the principal’s profit maximization facing agents who respond nonliearly to prices

Date/Time : 02 May 2019 16:00
Venue : S17 #06-11
Speaker : Zhang Shuangjian, École Nationale de la Statistique et de l'Administration Économique, Paris, France

Date/Time:02 May 2019 16:00 Venue: S17 #06-11 Speaker: Zhang Shuangjian, École Nationale de la Statistique et de l’Administration Économique, Paris, France On concavity of the principal’s profit maximization facing agents who respond nonliearly to prices A monopolist wishes to maximize her profits by finding an optimal price policy. After she announces a menu of products and prices, each agent will choose to buy that product which maximizes his own utility, if positive. The principal’s profits are the sum of the net earnings produced by each product sold. These are determined by the costs of production and the distribution of products sold, which in turn are based on the distribution of anonymous agents and the choices they make in response to the principal’s price menu. In this talk, we describe a necessary and sufficient condition for the convexity or concavity of the principal’s problem, assuming each agent’s disutility is a strictly increasing but not necessarily affine (i.e. quasilinear) function of the price paid. Concavity when present, makes the problem more amenable to computational and theoretical analysis; it is key to obtaining uniqueness and stability results for the principal’s strategy in particular. Even in the quasilinear case, our analysis goes beyond previous work by addressing convexity as well as concavity, by establishing conditions which are not only sufficient but necessary, and by requiring fewer hypotheses on the agents’ preferences. Moreover, the analytic and geometric interpretations of a specific condition relevant to the concavity of the problem have been explored. This talk represents joint work with Robert McCann. Add to calendar:

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18 Apr 2019
16:00
S17 #05-12 SR4

Tian Fangyang
National University of Singapore
Laplacian Equations from a Representation-Theoretic Point of View

Laplacian Equations from a Representation-Theoretic Point of View

Date/Time : 18 Apr 2019 16:00
Venue : S17 #05-12 SR4
Speaker : Tian Fangyang, National University of Singapore

Date/Time:18 Apr 2019 16:00 Venue: S17 #05-12 SR4 Speaker: Tian Fangyang, National University of Singapore Laplacian Equations from a Representation-Theoretic Point of View The classical Laplacian equation and wave equation are the basic examples of second order PDE. The fundamental solutions of them, which have been well studied, play an important role in the theory of these equations. A nice feature of these two equations is that the differential operator is invariant under certain classical group, hence one may expect a representation theoretic explanation of these equations. The (indefinite) Laplacian equations serve as a natural generalization of classical Laplacian equation and wave equation. In this talk, I will follow Howe and Tan’s exposition to discuss the (indefinite) Laplacian equation from a representation-theoretic point of view. We will cover some basic representation theory of (sl(2,R), so(2))-module, Weil representation of \tilde{SL(2,R)}, and the fundamental solutions of the indefinite Laplacian Equation. Add to calendar:

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17 Apr 2019
15:00
S17 #04-04 SR3

Zeng Fanhai
National University of Singapore
Fast time-stepping method for fractional integral and derivative operators

Fast time-stepping method for fractional integral and derivative operators

Date/Time : 17 Apr 2019 15:00
Venue : S17 #04-04 SR3
Speaker : Zeng Fanhai, National University of Singapore

Date/Time:17 Apr 2019 15:00 Venue: S17 #04-04 SR3 Speaker: Zeng Fanhai, National University of Singapore Fast time-stepping method for fractional integral and derivative operators We develop two fast time-stepping methods with linear complexity to calculate the discrete convolution for the approximation of the fractional integral and derivative operators. The effectiveness of the fast methods are verified through a series of numerical examples for long-time integration, including a numerical study of a fractional reaction-diffusion model. Add to calendar:

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17 Apr 2019
17:00
S17 #04-06 SR1

Liu Tianyu

Arithmetic algorithm of surreal numbers

Arithmetic algorithm of surreal numbers

Date/Time : 17 Apr 2019 17:00
Venue : S17 #04-06 SR1
Speaker : Liu Tianyu,

Date/Time:17 Apr 2019 17:00 Venue: S17 #04-06 SR1 Speaker: Liu Tianyu Arithmetic algorithm of surreal numbers The surreal number system is a totally ordered proper class containing the real numbers as well as infinite and infinitesimal numbers. A surreal number is sometimes defined as a function from an initial segment of the ordinals into the set $(+,-)$, usually leads to an infinite sign sequence. It can also be expressed uniquely in a normal form, as $\sum_{i<\alpha} \omega^{a_i}r_i$. In this talk I will present some algorithms for addition, multiplication and division on the real field. Besides, we will cover the normal form and sign sequence of surreal numbers, which will be crucial for arithmetic algorithm of surreal numbers of length $>\omega$. Add to calendar:

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17 Apr 2019
15:00
S17 #05-11 SR5

Oscar Garcia-Prada
ICMAT, Madrid
Higgs bundles and higher Teichmüller spaces

Higgs bundles and higher Teichmüller spaces

Date/Time : 17 Apr 2019 15:00
Venue : S17 #05-11 SR5
Speaker : Oscar Garcia-Prada , ICMAT, Madrid

Date/Time:17 Apr 2019 15:00 Venue: S17 #05-11 SR5 Speaker: Oscar Garcia-Prada, ICMAT, Madrid Higgs bundles and higher Teichmüller spaces Some connected components of a moduli space are mundane in the sense that they are distinguished only by obvious topological invariants or have no special characteristics. Others are more alluring and unusual either because they are not detected by primary invariants, or because they have special geometric significance, or both. In this talk, I will describe examples of such special components in moduli spaces of G-Higgs bundles on closed Riemann surfaces or, equivalently, moduli spaces of surface group representations into a semisimple Lie group G. These special components are related to higher Teichmüller theory and the notion of positivity for Anosov representations recently introduced by Guichard and Wienhard. Add to calendar:

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15 Apr 2019
17:00
S17 #06-11

Lin Wayne, Lu Jianlong, Lim Zhan Feng, An X
National University of Singapore
Black Hole Quartet

Black Hole Quartet

Date/Time : 15 Apr 2019 17:00
Venue : S17 #06-11
Speaker : Lin Wayne, Lu Jianlong, Lim Zhan Feng, An X, National University of Singapore

Date/Time:15 Apr 2019 17:00 Venue: S17 #06-11 Speaker: Lin Wayne, Lu Jianlong, Lim Zhan Feng, An X, National University of Singapore Black Hole Quartet We will present four 15-minute introductory talks on black holes: i) An introduction to black hole (by Lin Wayne) ii) Frozen star paradox (by Lu Jianlong) iii) Gravitational collapse under spherical symmetry (by Lim Zhan Feng) iv) What’s inside a black hole? (by An Xinliang) Add to calendar:

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15 Apr 2019
16:00
S17 #06-11

Deng Changsong
Wuhan University
Space and Time-Fractional Equations: a Random Time-Change Approach

Space and Time-Fractional Equations: a Random Time-Change Approach

Date/Time : 15 Apr 2019 16:00
Venue : S17 #06-11
Speaker : Deng Changsong, Wuhan University

Date/Time:15 Apr 2019 16:00 Venue: S17 #06-11 Speaker: Deng Changsong, Wuhan University Space and Time-Fractional Equations: a Random Time-Change Approach I will talk about a class of non-local equations with fractional operators in time and space from the point of view of the probability theory. In particular, we establish the exact asymptotic formulas for the fundamental solution to the $n$-dimensional fractional heat equations in both time and space. Add to calendar:

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11 Apr 2019
16:00
S17 #05-12 SR4

Jiang Meiyue
Peking University
Q-CURVATURE EQUATION IN DIMENSION 1

Q-CURVATURE EQUATION IN DIMENSION 1

Date/Time : 11 Apr 2019 16:00
Venue : S17 #05-12 SR4
Speaker : Jiang Meiyue, Peking University

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10 Apr 2019
15:00
S17 #05-11 SR5

Wang Dong
National University of Singapore
Phase transition related to Lyapunov exponents in the model of product of complex Ginibre matrices

Phase transition related to Lyapunov exponents in the model of product of complex Ginibre matrices

Date/Time : 10 Apr 2019 15:00
Venue : S17 #05-11 SR5
Speaker : Wang Dong , National University of Singapore

Date/Time:10 Apr 2019 15:00 Venue: S17 #05-11 SR5 Speaker: Wang Dong, National University of Singapore Phase transition related to Lyapunov exponents in the model of product of complex Ginibre matrices In this talk we consider the product of M independent complex Ginibre matrices, each of size N x N. The singular values of the product random matrix as M goes to infinity, under proper scaling, are Lyapunov exponents of a toy dynamical system model. In this talk we consider the model as (1) M goes to infinity and N is fixed, (2) N goes to infinity and M is fixed, or (3) M, N both goes to infinity, and find the behaviour of the largest singular eigenvalues. We observe a phase transition as M/N is O(1). Add to calendar:

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