Colloquia & Seminars

Colloquia & seminar talks are scheduled from 1:30pm - 2:45pm on Thursday each week and usually take place in DMSC 104, unless otherwise noted below. Speakers give 50-minute presentations on various mathematical and statistical topics.

If you would like to meet with a speaker, please contact math@unr.edu to schedule a meeting. To receive email announcements about future talks and events, please subscribe to our email list by sending an email to sympa@lists.unr.edu with a blank subject line and the main body 'subscribe mathstat-announce EmailAddress FirstName LastName'.

We look forward to your participation in our upcoming colloquia!

Colloquia and Seminar Talks Schedule
DateSpeakerInstitutionTitleRoom
Sep. 13, 2018 Agnieszka Wylomanska Wroclaw University of Science and Technology How to Model Data with Anomalous Diffusion Behavior?
Click for Abstract...

The classical financial models are based on the standard Brownian diffusion-type processes. However, in the exhibition of some real market data (like interest or exchange rates) we observe characteristic periods of constant values. Moreover, in the case of financial data, the assumption of normality is often unsatisfied. In such cases the popular Vasiček model, that is a mathematical system describing the evolution of interest rates based on the Ornstein-Uhlenbeck process, seems not to be applicable. Therefore, we propose an alternative approach based on a combination of the popular Ornstein-Uhlenbeck process with a stable distribution and subdiffusion systems that demonstrate such a characteristic behavior. The probability density function of the proposed process can be described by a Fokker-Planck type equation and therefore it can be examined as an extension of the basic Ornstein-Uhlenbeck model. We propose the parameter's estimation method and calibrate the subordinated Vasiček model to the interest rate data.

DMSC 104
Sep. 20, 2018 Wei Yang UNR Overview of UNR School of Community Health Sciences
Biostatistics Program: Faculty, Research Interests and Projects
Click for Abstract...

TBA

DMSC 104
Sep. 27, 2018 Daniel Lautzenheiser UNLV Generalized Apollonian Packings and Hausdorff Dimension
Click for Abstract...

In this talk, we discuss counting methods which admit rigorous upper and lower bounds on the Hausdorff (or Besikovitch) dimension of two generalized Apollonian circle packings. We find that the Hausdorff dimension of each packing is strictly greater than that of the Apollonian packing, supporting the unsolved conjecture that, among the many possible disk tilings of the plane, the Apollonian packing has the smallest possible residual set dimension. The obtained bounds are also consistent with calculated heuristic estimates.

DMSC 104
Oct. 4, 2018 Mark Colarusso University of South Alabama Gelfand-Zeitlin Integrable Systems: Where Linear Algebra, Geometry, & Representation Theory meet
Click for Abstract...

In the 19th century, physicists were interested in determining the conditions under which the equations of motion for a classical mechanical system could be found by integrating a finite number of times. Such a system was said to be completely integrable. Using symplectic geometry, we can generalize the notion of an integrable system beyond the realm of physics and into Lie theory and representation theory. Such "abstract" integrable systems can be used to geometrically construct infinite dimensional representations of Lie algebras.
In this talk, I will discuss a family of integrable systems, the Gelfand-Zeitlin systems that arise from purely linear algebraic data. For an n x n complex matrix X, we consider the eigenvalues of all the i x i submatrices in the top left hand corner of X. These are known as Ritz values and play an important role in numerical linear algebra. We will see how questions about Ritz values naturally lead to the construction of the Gelfand-Zeitlin integrable systems. I will explain results about the geometric properties of these systems and indicate how they answer questions of Parlett and Strang about Ritz values. I will also show how this research provides the foundation for the geometric construction of a category of infinite dimensional representations of certain classical Lie algebras using the theory of quantization.

DMSC 104
Oct. 11, 2018 Allison Moore UC Davis Band surgery along knots and site-specific recombination on
circular DNA
Click for Abstract...

Band surgery is a topological operation that transforms a
link into a new link. When the operation is compatible with the orientations of the links involved, it is called coherent band surgery, otherwise it is called non-coherent. While coherent band surgery is relatively well-understood, non-coherent band surgery is less predictable. We will classify all band surgery operations from the trefoil knot to the $T(2, n)$ torus knots and links, by way of a related three-manifold problem that we solve by studying the Heegaard Floer d-invariants under integral surgery along knots in the lens space $L(3,1)$. Band surgery on knots is of independent interest in the biological sciences; it is especially important in modeling the action of enzymatic complexes on circular DNA molecules. We will discuss how reconnection by site-specific recombinases is modeled by
band surgery on knots and links and give some insight as to why torus knots are of special relevance in this context. Parts of this project are joint work with Lidman and Vazquez.

DMSC 104
Oct. 18, 2018 Edward J Bedrick University of Arizona Data Reduction Prior to Interface: What are the Consequences of Using Principal Component Scores to Make Group Comparisons in a Student's T-Test or ANOVA?
Click for Abstract...

There has been a significant recent development of statistical methods for inference with high-dimensional data. Despite these developments, biomedical researchers and computational scientists often use a simple two-step step process to analyze high dimensional data. First, the dimensionality is reduced using a standard technique such as principal component analysis, followed by a group comparison using a t-test or analysis of variance. In this talk, I will try to untangle a number of issues associated with this approach, starting with the simplest but most vexing question (since this is left unstated) - what hypothesis is being tested? I will use a combination of approaches, including asymptotics, analytical construction of worst case scenarios, and simulation based on actual data to address whether this approach is sensible. Although asymptotics will consider a non-sparse setting, some discussion of implications in sparse problems will be given.

DMSC 104
Oct. 25, 2018 TBA TBA TBA
Click for Abstract...

TBA

DMSC 104
Nov. 1, 2018 TBA TBA TBA
Click for Abstract...

TBA

DMSC 104
Nov. 8, 2018 TBA TBA TBA
Click for Abstract...

TBA

DMSC 104
Nov. 15, 2018 TBA TBA TBA
Click for Abstract...

TBA

DMSC 104
Nov. 29, 2018 TBA TBA TBA
Click for Abstract...

TBA

DMSC 104
Dec. 6, 2018 TBA TBA TBA
Click for Abstract...

TBA

DMSC 104
TBA TBA TBA TBA
Click for Abstract...

TBA

TBA
TBA TBA TBA TBA
Click for Abstract...

TBA

TBA
TBA TBA TBA TBA
Click for Abstract...

TBA

TBA
TBA TBA  TBA TBA
Click for Abstract...

TBA

TBA
TBA TBA TBA TBA
Click for Abstract...

TBA

TBA