Thursday, February 19th, 2015

Distinguished Visiting Professor Talk Series: Nicolas Sirolli, Universidad de Buenos Aires, Febuary 11th @4pm in Olin 372

Title: From Congruent Numbers to Modular Forms Abstract: A positive integer is called a congruent number if it is the area of a right triangle with rational sides. The problem of giving a criterion for deciding if a number is congruent has been open for hundreds of years. The best answer known was given by Tunnell in 1983, using many deep results from modern Number Theory. His work will give a completely satisfactory answer, once the Birch and Swinnerton-Dyer conjecture gets proved. In this talk we will introduce, in a way as friendly as possible, the main ingredients needed to understand Tunnell’s […]

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Monday, February 2nd, 2015

Student Talk Series: John Klobusicky, Geisinger Health Systems, February 5th, Olin 268 @ noon

Title: Piecewise Deterministic Markov Processes and Metal Grain Coarsening Abstract: In material science, individual metal grains obey surprisingly simple rules.  However, geometric considerations can create difficulties when attempting to analyze the bulk properties of metals.  In this talk, we’ll describe a mean field model using piecewise deterministic Markov processes which converts the geometric problem of grain evolution to one of analysis and stochastic processes.  In particular, we’ll show that densities of grains approach a law of large numbers described by a partial differential equation.

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Monday, February 2nd, 2015

Joint Talk with Management: Anne Robinson and John Williamson, Verizon Wireless, February 5th, Rooke CHEM 116 @ 3pm

Title: How Analytics Professionals Make the World Go Round Abstract: It’s hard to open a business magazine, walk through an airport or even participate in an executive meeting and NOT see or hear reference to analytics. Recognized as the currency of business, mathematics or analytics are empowering decision-making at new levels. A trend that started with CIOs is spreading throughout the C-Suite – Everyone wants ANALYTICS!   What exactly are these analytics professionals doing? What types of real-world problems are they solving? Are they actually applying the math, statistics and operations research tools they learned in their courses? What other skills […]

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Friday, January 16th, 2015

Student Talk Series: Tracy Sweet, University of Maryland, January 22nd, Olin 268 @ noon

Title: Hierarchical Social Network Models with Applications in the Social Sciences Abstract: The term “social network analysis” includes most quantitative methods for analyzing relational data and these methods are both exploratory and inferential. For inference, there are a variety of social network statistical models to represent the stochastic nature of network relationships.  In this talk, I will present social network models that are written as Hierarchical Bayes models and describe how these generative models can be used in the social sciences which often involve multiple partially exchangeable networks.

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Monday, November 24th, 2014

Distinguished Visiting Professor Talk Series: Sergi Elizalde, Dartmouth College, November 24th @4pm in Olin 372

Title: Consecutive patterns in permutations   Abstract: An occurrence of a consecutive pattern sigma in a permutation pi is a subsequence of adjacent entries of pi in the same relative order as the entries of sigma. For example, occurrences of the consecutive pattern 21 are descents, and alternating permutations are those that avoid the consecutive patterns 123 and 321. The systematic study of consecutive patterns in permutations started over a decade ago.  More recently, consecutive patterns have become relevant in the study of one-dimensional dynamical systems, and they are useful in creating tests to distinguish random from deterministic time series. We […]

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Tuesday, November 18th, 2014

Student Talk Series: Sergi Elizalde, Dartmouth College, November 20th, Olin 268 @ noon

Title: Lattice paths between two boundaries Abstract: Dyck paths are lattice paths with steps N=(0,1) and E=(0,1) starting at (0,0), ending at (n,n), and never going below the diagonal y=x. Among the many interesting facts known about Dyck paths, one is that the parameters ‘number of E steps at the end’ and ‘number of returns to the diagonal’ have a symmetric joint distribution, meaning that to each Dyck path we can bijectively associate another one where these parameters are interchanged. I will show that this symmetry property applies not only to Dyck paths, but more generally to lattice paths with N […]

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Friday, October 31st, 2014

Distinguished Visiting Professor Talk Series: Paola Sztajn, North Carolina State University, November 4, @ 4pm in Olin 372

Title: Learning from systematic descriptions of mathematics professional development Abstract:  In this talk I present emerging results from a systematic review of publications on mathematics professional development. The research team reviewed over 170 papers published between 1992 and 2010 to address the following research questions: What do we know about the design and conduct of mathematics PD being studied by researchers and how are these PD characterized in research reports? The conceptual framework included six elements: theory, context, goals, content, format, and activities.

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Thursday, October 23rd, 2014

Problem of the Week Instructions and This Week’s Problem

Try the Math Department Problem of the Week! New Problems every Tuesday at 1pm! How it Works: Pick up a problem sheet in the Math Department on the third floor of Olin Science Do the problem! Turn in your solution in the Math Dept. Office in Olin 380 before 5pm the following Monday. Every correct solution over the course of the semester gives you a chance to win a $50 Amazon Gift Card. Keep doing the Problem of the Week! Each correct solution adds your name to the drawing at the end of the semester! 2 correct solutions = 2 […]

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Monday, October 20th, 2014

Distinguished Visiting Professor Talk Series: Eva A. Gallardo Gutierrez, Universidad Complutense de Madrid, October 23rd @ 4pm in Olin 372

Title: Rota’s Universal Operators Abstract: The Invariant Subspace Problem for Hilbert spaces is a long-standing question and the use of universal operators in the sense of Rota has been one tool for studying the problem. The best known universal operators have been adjoints of analytic Toeplitz operators or unitarily equivalent to them. We present many examples of Toeplitz operators whose adjoints are universal operators and exhibit some of their common properties. Some ways in which the invariant subspaces of these universal operators interact with operators in their commutants are given. Special attention is given to the closed subalgebra, not always the zero […]

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Wednesday, October 15th, 2014

Algebra etc. Seminar: Shelby Kilmer, October 16 @ 4pm in Olin 372

Title: Random Groups at Density 1/2 Abstract: Random groups in the density model (with density 0<d<1) have presentations with a random set of (2m-1)^{dk} relators of length k on m generators. The classic theorem in the density model states that for d>1/2, random groups are asymptotically almost surely trivial or isomorphic to Z/2Z, while for d<1/2, random groups are asymptotically almost surely infinite hyperbolic. This summer our research group studied random groups at d=1/2 and found both infinite hyperbolic groups and trivial groups are generic, depending on how we tuned certain parameters.

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