Probabilistic Method in Combinatorics
- Series
- Undergraduate Seminar
- Time
- Monday, September 14, 2020 - 15:30 for 1 hour (actually 50 minutes)
- Location
- Bluejeans meeting https://bluejeans.com/759112674
- Speaker
- Dr. Lutz Warnke – Georgia Tech
Please Note: Join us live via Bluejeans https://bluejeans.com/759112674 for this talk.
Mathematics can help all of us sort through some complicated scenarios, with changing inputs, and changing conclusions. I will illustrate this with some examples. Porker hands and Jury selection bias: Expert testimony that I gave in a death penalty case. Specificity of testing: A random person tests positive for COVID. Do they have the disease? Designing pooled testing for the disease. When is it effective?
Please Note: The live talk will be broadcast on Bluejeans: https://gatech.bluejeans.com/759112674
I will present a proof of Gauss's Law of Quadratic Reciprocity based on permutations and the mathematics of dealing cards.
Domino tilings of finite grid regions have been studied in many contexts, revealing rich combinatorial structure. They arise in applications spanning physics, computer science and probability theory and recreational mathematics. We will look at questions such as counting and sampling from large combinatorial sets, such as the set of domino tilings, providing a small sample of some of the techniques that are used.
Did you know that a wheel or a ball bearing does not need to be round? Convex regions that can roll smoothly come in many remarkable shapes and have practical applications in engineering and science. Moreover, the mathematics used to describe them, known as convex geometry, is a subject that beautifully ties together analysis and geometry. I'll bring some of these objects along and tell the class how to describe them effectively and recount their interesting history.
Surfaces are some of the most basic examples of spaces. Although topologists have studied surfaces for a long time, they continue to fascinate. I'll give an overview of the study of surfaces over the past 150 years by highlighting work of seven mathematicians. We'll discuss the classification of surfaces, and we'll also discuss mapping class groups, which are collections of symmetries of surfaces. I'll also give the flavor of four of my own research projects about surfaces, one for each of four broad mathematical areas: group theory, geometry, topology, and dynamics.
The Probabilistic Method is a powerful tool for tackling many problems in discrete mathematics and related areas.
Roughly speaking, its basic idea can be described as follows. In order to prove existence of a combinatorial structure with certain properties, we construct an appropriate probability space, and show that a randomly chosen element of this space has the desired property with positive probability.
In this talk we shall give a gentle introduction to the Probabilistic Method, with an emphasis on examples.
As a geometric group theorist, my favorite type of manifold is a surface and my favorite way to study surfaces is by considering the mapping class group, which is the collection of symmetries of a surface. In this talk, we will think bigger than your average low-dimensional topologist and consider surfaces of infinite type and their associated “big” mapping class groups.