** Analysis and Applications (AaA) Seminar at UCCS**

This seminar is intended to have a very informal format, and welcomes faculty and grad students from the Pikes Peak region who are interested in contemporary research in analysis (of all sorts) and applications. Areas covered include but are not limited to real and complex analysis, functional analysis, harmonic analysis, ODEs and PDEs, mathematical physics and applications to nonlinear phenomena, numerical analysis, scientific computation and other fields (too many to enumerate).

**Fall 2018
Wednesdays 4:30-5:30pm
UC 309, UCCS campus**

**Sep 12, 2018 - TBA****Oct 3, 2018 - TBA****Oct 17, 2018 - TBA
Oct 31, 2018 - TBA
Nov 14, 2018 - TBA
Dec 5, 2018 - TBA**

Please contact Dr. Radu Cascaval (radu@uccs.edu) if you are interested to join this seminar or need more info.

Limited number of parking passes will be made available to non-UCCS individuals attending this seminar.

** PAST SEMESTERS**

**Spring 2018**

**Apr 11, 2018 - Greg Fasshauer, Colorado School of Mines***An Introduction to Kernel-Based Approximation Methods*

**Mar 14, 2018 - Ethan Berkove, Lafayette College (joint with the "Rings and Wings" seminar)***Short Paths and Long Titles: Travels through the Sierpinski carpet, Menger sponge, and beyond. *

**Feb 28, 2018 - Radu Cascaval, UCCS ***Traffic Flow Models. A Tutorial*

__Fall 2017____ __

**Dec 8, 2017 - Dr. Barbara Prinari, UCCS ***Solitons and rogue waves for a square matrix nonlinear Schrodinger equationwith nonzero boundary conditions*

**Nov 17, 2017 - Dr. Oksana Bihun, UCCS *** **New properties of the zeros of Krall polynomials*

**Oct 27, 2017 - Dr. Radu Cascaval, UCCS***What do Analysis and Scientific Computation have in common ...*

**Sep 29, 2017 - Inaugural Seminar: Dr. Fritz Gesztesy, Baylor U***The eigenvalue counting function for Krein-von Neumann extensions of elliptic operators* ** **

**TITLES & ABSTRACTS:**

** **

*Apr 11, 2018 Seminar*

**Speaker: Dr. Greg Fasshauer, Colorado School of Mines****Title: **

*An Introduction to Kernel-Based Approximation Methods*

**Abstract: **** ****I will start with a few historical remarks, and then motivate the use of kernel-based approximation as a numerical approach that generalizes standard polynomial-based methods. Examples of kernels and their use in data fitting problems will be provided along with an overview of some of the concerns and issues associated with the use of kernel methods.***************************************************************** **

*Mar 14, 2018 Seminar*

**Speaker: Dr. Ethan Berkove, Laffayette College (Joint with Rings and Wings Seminar)****Title: Short Paths and Long Titles: Travels through the Sierpinski carpet, Menger sponge, and beyond. **

**Abstract: ** Sierpinski carpet and Menger sponge are fractals which can be thought of as two and three dimensional versions of the Cantor set. Like the Cantor set, each is formed by starting with a shape (a square for the carpet, a cube for the sponge) and then recursively removing certain subsets of it. Unlike the Cantor set, what remains is connected in the following sense: given any two points s and f in the carpet or sponge, there is a path from s to f that stays in the carpet or sponge. In this talk, we’ll discuss what we know about the shortest path from s to f in the carpet, sponge, and even higher dimensional versions of these fractals. The proofs required a surprising (at least to us) breadth of techniques, from combinatorics, geometry, and even linear programming. (Joint work with Derek Smith)

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*Feb 28, 2018 Seminar*

**Speaker: Dr. Radu Cascaval, UCCS****Title: Traffic Flow Models. A Tutorial**

**Abstract: **We present several traffic flow models, both at the micro- and macro-scale, including for multi-lane traffic. Problems of controlling the traffic will be described and numerical simulations will illustrate possible solutions.

***************************************************************Dec 8, 2017 Seminar **

**Speaker: Dr. Barbara Prinari, UCCS****Title: Solitons and rogue waves for a square matrix nonlinear Schrodinger equation with nonzero boundary conditions**

**Abstract: **In this talk we discuss the Inverse Scattering Transform (IST) under nonzero boundary conditions for a square matrix nonlinear Schrodinger equation which has been proposed as a model to describe hyperfine spin F = 1 spinor Bose-Einstein condensates with either repulsive interatomic interactions and anti-ferromagnetic spin-exchange interactions, or attractive interatomic interactions and ferromagnetic spin-exchange interactions. Emphasis will be given to a discussion of the soliton and rogue wave solutions one can obtain as a byproduct of the IST.

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*Nov 17, 2017 Seminar*

**Speaker: Dr. Oksana Bihun, UCCS****Title: New properties of the zeros of Krall polynomials**

**Abstract: **We identify a class of remarkable algebraic relations satisfied by the zeros of the Krall orthogonal polynomials that are eigenfunctions of linear differential operators of order higher than two. Given an orthogonal polynomial family p_n(x), we relate the zeros of the polynomial p_N with the zeros of p_m for each m <=N (the case m = N corresponding to the relations that involve the zeros of pN only). These identities are obtained by exacting the similarity transformation that relates the spectral and the (interpolatory) pseudospectral matrix representations of linear differential operators, while using the zeros of the polynomial p_N as the interpolation nodes. The proposed framework generalizes known properties of classical orthogonal polynomials to the case of non-classical polynomial families of Krall type. We illustrate the general result by proving new remarkable identities satisfied by the Krall-Legendre, the Krall-Laguerre and the Krall-Jacobi orthogonal polynomials.

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*Oct 27, 2017 Seminar*

**Speaker: Dr. Radu C. Cascaval, UCCS****Title: What do Analysis and Scientific Computation have in common ...**

**Abstract: **Analysis, the world of the infinitesimally small, is thought to be one of the last standing outposts where humans can fight the computational invasion. In spite of this fact, computational sciences continue to benefit greatly from advances in analysis. This talk will illustrate this relationship, in particular functional analysis connections to numerical spectral methods, meshless methods, and their applications to numerical solutions to PDEs.

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*Sept 29, 2017 Seminar*

**Speaker: Dr. Fritz Gesztesy, Baylor University****Title: The eigenvalue counting function for Krein-von Neumann extensions of elliptic operators (Slides)**

**Abstract: **We start by providing a historical introduction into the subject of Weyl-asymptotics for Laplacians on bounded domains in n-dimensional Euclidean space, and a brief introduction into the basic principles of self-adjoint extensions. Subsequently, we turn to bounds on eigenvalue counting functions and derive such a bound for Krein-von Neumann extensions corresponding to a class of uniformly elliptic second order PDE operators (and their positive integer powers) on arbitrary open, bounded, n-dimensional subsets \Omega in R^n. (No assumptions on the boundary of \Omega are made; the coefficients are supposed to satisfy certain regularity conditions.) Our technique relies on variational considerations exploiting the fundamental link between the Krein-von Neumann extension and an underlying abstract buckling problem, and on the distorted Fourier transform defined in terms of the eigenfunction transform of the corresponding differential operator suitably extended to all of R^n. We also consider the analogous bound for the eigenvalue counting function for the corresponding Friedrichs extension. This is based on joint work with M. Ashbaugh, A. Laptev, M. Mitrea, and S. Sukhtaiev.

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