Probability Archives - Page 8 of 8

Seminars: Probability

Date
Time
Venue

Speaker
Affiliation
Title of Talk

26 Apr 2018
15:00
S17 #04-06 SR1

Adam Bowditch
National University of Singapore
Trapping mechanisms for random walks on Galton-Watson trees

Trapping mechanisms for random walks on Galton-Watson trees

Date/Time : 26 Apr 2018 15:00
Venue : S17 #04-06 SR1
Speaker : Adam Bowditch , National University of Singapore

Date/Time:26 Apr 2018 15:00 Venue: S17 #04-06 SR1 Speaker: Adam Bowditch, National University of Singapore Trapping mechanisms for random walks on Galton-Watson trees In a range of models of random walks in random environments, the asymptotic behaviour of the walk is driven by a trapping mechanism arising due to adverse regions in the environment. Random walks on trees are a natural example as dead-ends in the tree form traps which slow the walk. In this talk, we discuss biased random walks on both supercritical and subcritical Galton-Watson trees conditioned to survive. In particular, we describe how the trapping observed in these models is influenced by the structure of the tree and focus on questions concerning the existence of a limiting speed, the scale of the fluctuations and the issues concerning functional results. Add to calendar:

Add to calendar :

29 Mar 2018
15:00
S17 #04-06 SR1

Vadim Gorin
MIT
Convolutions and fluctuations: free, finite, quantized

Convolutions and fluctuations: free, finite, quantized

Date/Time : 29 Mar 2018 15:00
Venue : S17 #04-06 SR1
Speaker : Vadim Gorin , MIT

Date/Time:29 Mar 2018 15:00 Venue: S17 #04-06 SR1 Speaker: Vadim Gorin, MIT Convolutions and fluctuations: free, finite, quantized The talk is about three operations on eigenvalues of self-adjoint matrices obtained from cutting out principal corners, adding and multiplying matrices. We discuss the asymptotic behavior of the operations as the size of the matrix goes to infinity, or as the dimension of the base field (beta parameter) goes to infinity, or in the quantized problem where matrices are replaced by group representations. The first one is classical, the third one is more recent, and the second one is very new. Each case leads to its own operation on measures and its own Gaussian fluctuation field. Add to calendar:

Add to calendar :

22 Mar 2018
15:00
S17 #04-06 SR1

Andrei Florin Deneanu
Yale University
How often is a random matrix normal?

How often is a random matrix normal?

Date/Time : 22 Mar 2018 15:00
Venue : S17 #04-06 SR1
Speaker : Andrei Florin Deneanu, Yale University

Date/Time:22 Mar 2018 15:00 Venue: S17 #04-06 SR1 Speaker: Andrei Florin Deneanu, Yale University How often is a random matrix normal? When the matrix entries have a continuous distribution, the probability is zero, as the set of normal matrices, viewed as points in R^{n^2}, is not full dimensional. However, for discrete distributions, the situation is totally different. We are going to focus on the Rademacher matrix, whose entries take values 1 and -1 with equal probabilities and prove an upper bound of 2^{-(0.3+o(1))n^2} for the probability in question. Note also that a lower bound of 2^{-(0.5+o(1))n^2} is given by the fact that every symmetric matrix is normal. Add to calendar:

Add to calendar :

12 Feb 2018
16:00
S17 #04-05 SR2

Akira Sakai
Hokkaido University
Hyperscaling for oriented percolation in 1+1 space-time dimensions

Hyperscaling for oriented percolation in 1+1 space-time dimensions

Date/Time : 12 Feb 2018 16:00
Venue : S17 #04-05 SR2
Speaker : Akira Sakai, Hokkaido University

Date/Time:12 Feb 2018 16:00 Venue: S17 #04-05 SR2 Speaker: Akira Sakai , Hokkaido University Hyperscaling for oriented percolation in 1+1 space-time dimensions Consider nearest-neighbor oriented percolation in d+1 space-time dimensions. Let \rho,\eta, \nu be the critical exponents for the survival probability up to time t, the expected number of vertices at time t connected from the space-time origin, and the gyration radius of those vertices, respectively. We prove that the hyperscaling inequality d \nu >= \eta+2\rho, which holds for all d>=1 and is a strict inequality above the upper-critical dimension 4, becomes an equality for d=1, i.e., \nu=\eta+2\rho, provided existence of at least two among \rho,\eta,\nu. The key to the proof is the recent result on the critical box-crossing property by Duminil-Copin, Tassion and Teixeira (2017). Add to calendar:

Add to calendar :