Math Club will meet again next Wednesday 4/25 for our last meeting of the semester. See you then!

## Statistical Analysis of Social Networks

This week our speaker is Krista Gile. Her talk “Statistical Analysis of Social Networks,” will be Wednesday at 5:30 PM in LGRT 1634. Pizza and soda will be provided with the talk. Hope to see you there!

Abstract:

Human populations are often connected by social networks of relations. Such social networks may either be of direct interest to researchers, or useful in designing sampling strategies through which to reach population members. Most existing strategies for statistical inference focus on cases where the full social network is observed. This talk will describe some types of analysis often done using social networks, then talk in detail about an application using a network to sample from a hard-to-reach population: estimating the HIV prevalence among injecting drug users.

## Computational Fluid Dynamics

This week Hans Johnston will talk about computational fluid dynamics. There will be pizza and soda with the talk. See you at 5:30 on Wednesday in LGRT 1634!

Abstract: We will discuss some current methods as well as future challenges in CFD.

## Three Houses and Three Utilities

This week our speaker is Elizabeth Drellich. Her talk, “The Three Houses and Three Utilities Problem: on Earth and on a Torus” will be accompanied by pizza and soda this Wednesday 3/7 at 5:30 in LGRT 1634. Hope to see you there!

Abstract:

The Three Houses and Three Utilities Problem asks, can you draw lines, called edges, connecting each of the three houses to each of the three utilities with no lines crossing each other. The first part of the talk will explain the problem in terms of graph theory, and discuss how to tell whether a graph is planar, (i.e. can be drawn with no crossings). But what happens when a graph isn’t planar, like the one that results from the three houses three utilities problem? Then we have to add bridges to allow on edge to go over another. Determining a graph’s genus tells us the minimum number of bridges needed to make sure that no two edges cross.

## Self-Similarity: Geometric Series, Games with Checkers, and the Golden Ratio

This week our speaker is Daniel Briggs. He will talk about “Self-Similarity: Geometric Series, Games with Checkers, and the Golden Ratio.” Come listen and enjoy free pizza and soda this Wednesday at 5:30 in LGRT 1634.

Abstract:

A lot of great math has resulted from investigating interesting ways to compare a thing to itself. For example, crystals and fractals can be formulated mathematically and studied in terms of their self-similarity, and they have far-reaching impact on science. Our first focus will be to view infinite geometric series in terms of their relationship to themselves, and use them to investigate some self-similar games with checkers. The golden ratio shows up, which provides a good opportunity to talk about pentagons and Fibonacci numbers. At the end, there will be a brief discussion of how the idea of self-similarity plays a role in modern mathematics.

## Movie Night 2/8/12

This Wednesday at 5:30 PM in LGRT 1634 we will be showing the documentary, “N is a Number: A Portrait of Paul Erdos.” The movie is about the life of Paul Erdos, the most prolific mathematician that ever lived. Come enjoy free pizza and soda while you watch. Talks will begin next week!

## Job Searching for Math Majors

This Wednesday 11/30 from 5:30-6:30 in LGRT 1634, Mary Ellen Liseno, Assistant Director of Career Planning for the College of Natural Sciences, will visit the Math Club. She will give an overview of the job search process with an emphasis on job searching and interviewing. This is also a great opportunity to learn more about the resources UMass’s Career Services has to offer. Pizza and soda will be available!

## Telling Knots Apart: Knots and Knot Invariants

This Wednesday at 5:30 in LGRT 1634 Tobias Wilson will present “Telling Knots Apart: Knots and Knot Invariants.” Come listen and stay warm! We will have pizza and soda with the talk.

Abstract:

We will define knots to be exactly what you’d think they should be and then consider one of the big questions of knot theory: many knots that look different turn out to be equivalent. With the help of pipe-cleaner models, we’ll develop some knot invariants, culminating in the HOMFLY polynomial. This talk will be completely accessible to students at any level.

## Pythagoras at the Bat: An Introduction to Statistics and Modelling

Calling all baseball fans! Just in time for the Worlds Series, Professor Steven J. Miller from Williams College will present “Pythagoras at the Bat: An Introduction to Statistics and Modelling.” Come listen and enjoy free pizza and soda! Note that this week Math Club will meet in ****LGRT 1528**** at the usual time, 5:30-6:30.

Abstract:

Let RS (resp., RA) denote the average number of runs scored (resp., allowed) in a baseball game by a team. It was numerically observed years ago that a good predictor of a team’s won-loss percentage is RS^{2} / (RS^{2} + RA^{2}), though no one knew WHY the formula worked. We review elementary concepts of probability and statistics and discuss how one can build and solve a model for this problem. In the course of investigating this problem we discuss how one attacks problems like this in general (what are the features of a good model, how to solve it, and so on). The only pre-requisite is simple calculus (no baseball knowledge is required, though Red Sox knowledge is always a plus, unless those bums played so poorly that they didn’t make the playoffs!).

## Minesweeper and the Million-Dollar Math Problem

This week our speaker is Jeffrey Hatley. He will talk to us about “Minesweeper and the Million-Dollar Math Problem.” Come listen and enjoy free pizza and soda from 5:30-6:30 in LGRT 1634!

Abstract:

One of the most important questions in mathematics and theoretical computer science today is whether P = NP; roughly speaking, this question asks whether certain problems are truly as “hard” as they appear to be. In this talk, we will make precise the definition of a “hard” problem and discuss some of the implications of a yes or no answer to the P vs. NP question. Finally, we will explain its surprising relationship to the popular computer game and procrastination tool Minesweeper.