Seminars and Colloquia by Series

The extremal function for $K_p$ minors

Series
Other Talks
Time
Tuesday, November 6, 2018 - 12:30 for 30 minutes
Location
Skiles 006
Speaker
Dantong Zhu – Georgia Tech –

Please Note: This talk is organized by the Association for Women in Math (AWM). Everyone is welcome to attend.

In 1968, Mader showed that for every integer $p = 1, 2, …, 7$, agraph on $n \geq p$ vertices and at least $(p-2)n - \binom{p-1}{2} + 1$ edgeshas a $K_p$ minor. However, this result is false for $p = 8$ with the counter-example K2,2,2,2,2. In this talk, we will discuss this function presented byMader for $K_p$ where $p$ is bigger. We will also discuss related resultsproved using probabilistic methods and the relation of this problem toHadwiger’s conjecture.

Quantum Chaos, Thermalization, and Localization

Series
Other Talks
Time
Tuesday, November 6, 2018 - 11:00 for 1 hour (actually 50 minutes)
Location
Howey N110
Speaker
Brian Swingle – Univ of Maryland
I will discuss chaos in quantum many-body systems, specifically how it is relates to thermalization and how it fails in many-body localized states. I will conjecture a new universal form for the spreading of chaos in local systems, and discuss evidence for the conjecture from a variety of sources including new large-scale simulations of quantum dynamics of spin chains.

Gabor Lugosi lectures on combinatorial statistics (3 of 3)

Series
Other Talks
Time
Thursday, October 25, 2018 - 11:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Lectures on Combinatorial Statistics – Pompeu Fabra University, Barcelona –

Please Note: Thanks are due to our colleague, Vladimir Koltchinskii, for arranging this visit. Please write to Vladimir if you would like to meet with Professor Gabor Lugosi during his visit, or for additional information.

In these lectures we discuss some statistical problems with an interesting combinatorial structure behind. We start by reviewing the "hidden clique" problem, a simple prototypical example with a surprisingly rich structure. We also discuss various "combinatorial" testing problems and their connections to high-dimensional random geometric graphs. Time permitting, we study the problem of estimating the mean of a random variable.

Gabor Lugosi lectures on combinatorial statistics (2 of 3)

Series
Other Talks
Time
Thursday, October 18, 2018 - 15:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Lectures on Combinatorial Statistics – Pompeu Fabra University, Barcelona –

Please Note: Thanks are due to our colleague, Vladimir Koltchinskii, for arranging this visit. Please write to Vladimir if you would like to meet with Professor Gabor Lugosi during his visit, or for additional information.

In these lectures we discuss some statistical problems with an interesting combinatorial structure behind. We start by reviewing the "hidden clique" problem, a simple prototypical example with a surprisingly rich structure. We also discuss various "combinatorial" testing problems and their connections to high-dimensional random geometric graphs. Time permitting, we study the problem of estimating the mean of a random variable.

Undergraduate Seminar (extra thursday lecture): When triangles turn square

Series
Other Talks
Time
Thursday, October 18, 2018 - 12:05 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Boris Bukh – Carnegie Mellon University
What to do if the measurements that you took were corrupted by a malicious spy? We will see how the natural geometric approach to the problem leads to a geometry where lines are crooked, and triangles are square.

Gabor Lugosi lectures on combinatorial statistics (1 of 3)

Series
Other Talks
Time
Monday, October 15, 2018 - 12:00 for 1 hour (actually 50 minutes)
Location
Groseclose 402
Speaker
Lectures on Combinatorial Statistics – Pompeu Fabra University, Barcelona –

Please Note: Thanks are due to our colleague, Vladimir Koltchinskii, for arranging this visit. Please write to Vladimir if you would like to meet with Professor Gabor Lugosi during his visit, or for additional information.

In these lectures we discuss some statistical problems with an interesting combinatorial structure behind. We start by reviewing the "hidden clique" problem, a simple prototypical example with a surprisingly rich structure. We also discuss various "combinatorial" testing problems and their connections to high-dimensional random geometric graphs. Time permitting, we study the problem of estimating the mean of a random variable.

The Seven Bridges of Königsberg

Series
Other Talks
Time
Thursday, September 13, 2018 - 11:05 for 2 hours
Location
Plaza along Atlantic Drive
Speaker
Evans Harrell, Kristel Tedesco, Chaowen Ting, musicians, and performers – Georgia Tech –
This is an interdisciplinary event using puzzles, story-telling, and original music and dance to interpret Euler's analysis of the problem of the Seven Bridges of Königsberg, and the birth of graph theory. Beginning at 11:00, students from GT's Club Math will be on the plaza between the Howie and Mason Buildings along Atlantic Dr., with information and hands-on puzzles related to Euler and to graphs. At 12:00 the performance will begin, as the GT Symphony Orchestra and a team of dancers interpret the story of the Seven Bridges. For more information see the news article at http://hg.gatech.edu/node/610095.

Global Finite-Energy Solutions to the Maxwell-Pauli-Coulomb Equations

Series
Other Talks
Time
Thursday, September 6, 2018 - 10:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Forrest Kieffer – Georgia Tech –
The three-dimensional Maxwell-Pauli-Coulomb (MPC) equations are a system of nonlinear, coupled partial differential equations describing the time evolution of a single electron interacting with its self-generated electromagnetic field and a static (infinitly heavy) nucleus of atomic number Z. The time local (and, hence, global) well-posedness of the MPC equations for any initial data is an open problem, even when Z = 0. In this talk we present some progress towards understanding the well-posedness of the MPC equations and, in particular, how the existence of solutions depends on the stability of the one-electron atom. Our main result is that time global finite-energy weak solutions to the MPC equations exist provided Z is less than a critical charge. This is an oral comprehensive exam. All are welcome to attend.

Twisting polynomials: new directions in the study of Thurston maps

Series
Other Talks
Time
Tuesday, August 14, 2018 - 14:00 for 1 hour (actually 50 minutes)
Location
Skiles 154
Speaker
Justin Lanier – Georgia Tech –
Take a branched covering map of the sphere over itself so that the forward orbit of each critical point is finite. Such maps are called Thurston maps. Examples include polynomials with well-chosen coefficients acting on the complex plane, as well as twists of these by mapping classes. Two basic problems are classifying Thurston maps up to equivalence and finding the equivalence class of a Thurston map that has been twisted. We will discuss ongoing joint work with Belk, Margalit, and Winarski that provides a new, combinatorial approach to the twisted polynomial problem. We will also propose several new research directions regarding Thurston maps. This is an oral comprehensive exam. All are welcome to attend.

IBM PonderThis monthly challenge

Series
Other Talks
Time
Tuesday, April 10, 2018 - 11:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Prof. Oded Margalit – CTO, IBM Cyber security center of excellence at Ben Gurion, University of the Negev

Please Note: [CV: Prof. Oded Margalit, PhD in Computer Science from Tel-Aviv University under the supervision of Prof. Zvi Galil has worked at IBM's Haifa research lab on machine learning, constraint satisfaction, verification and more. Currently he is the CTO of the IBM Cyber security center of excellence at Ben Gurion University of the Negev. Oded participates in organising several computer science competitions (like the international IEEEXtreme and the national CodeGuru). He loves riddles and authors the monthly challenge corner of IBM research: "Ponder-This".]

IBM research runs a mathematical challenge site. Every month a new challenge is posted; as well as a solution for the previous month's riddle. Prof. Oded Margalit is the puzzlemaster, for the last decade. In the talk, he will survey some of the riddles over the years, and tell some anecdotes about the challenges and the solvers. For example: A PRL paper born from a riddle on random walks; ITA-2014 paper on water hose model (using quantum entanglement to break location based encryption); Games: 2048, Kakuro, Infinite chess game, the probability of a backgammon to end with a double, Fisher Foul Chess and more. Minimal hash function, Combinatorial Test Design; A solver from Intensive Care Unit and other stories; Finding a natural number n such that round ((1+2 cos(20))^n) is divisible by 10^9; We'll leave you with a still open question about Permutation-firing cannon... Don't worry - no high math knowledge is assumed.

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