# Calendar

## Today

### Coffee, Tea & Cookie Time

Monday, Nov 20 3:15 pm - 3:45 pm

Refreshments served in the Library Lounge

### CCAM Seminar, Yunan Yang, University of Texas at Austin, UNIV 103

Monday, Nov 20 4:30 pm - 5:30 pm

## Transport for Seismic Inversion

Abstract: Optimal transport has become a well-developed topic in the analysis since it was first proposed by Monge in 1781. Due to their ability to incorporate differences in both intensity and spatial information, the related Wasserstein metrics have been adopted in a variety of applications, including seismic inversion. The quadratic Wasserstein metric ($W_2$) has ideal properties like convexity and insensitivity to noise, while conventional $L^2$ norm is known to suffer from local minima. We propose two ways of using W2 in seismic inversion, a trace-by-trace comparison solved by 1D exact formula, and the global comparison which requires the numerical solution of Monge-Ampère equation. The 1D approach has been successfully applied to field data in collaboration with PGS, Inc. I will discuss the connection between the Wasserstein metric $W_p$ and the Sobolev space $W^{-1,p}$. This is a joint work with Dr. Björn Engquist, Brittany Froese, Junzhe Sun and Lingyun Qiu.

## Wednesday

### Thanksgiving Break

Wednesday, Nov 22 - Friday, Nov 24

University closed Thursday and Friday.

## Next Week

### Coffee, Tea & Cookie Time

Monday, Nov 27 3:15 pm - 3:45 pm

Refreshments served in the Library Lounge

### CCAM Seminar, Dr. Xiu Yang , Pacific Northwest National Lab, UNIV 103

Monday, Nov 27 4:30 pm - 5:20 pm

## Alternating direction method for enhancing sparsity of the representation of uncertainty

Abstract: Compressive sensing has become a powerful tool for uncertainty quantification when only limited data is available. We provide a general framework using alternating direction method to enhance the sparsity of the representation of uncertainty in the form of generalized polynomial chaos expansion. This method identifies new sets of random variables through iterative rotations such that the new representation of the uncertainty using these variables is sparser. Consequently, we increase both the efficiency and accuracy of the compressive sensing-based uncertainty quantification method. We demonstrate the effectiveness of this method with applications in analyzing uncertainties in high-dimensional complex systems.

### Colloquium Refreshments

Tuesday, Nov 28 3:00 pm - 3:30 pm

Refreshments served in the Library Lounge prior to Colloquium.

### Special Colloquium, Prof. Preston Wake, UCLA, REC 123

Tuesday, Nov 28 4:30 pm - 5:20 pm

## Quantifying congruences between Eisenstein series and cusp forms

Consider the following two problems in algebraic number theory:

1. For which prime numbers p can we easily show that the Fermat equation x^p + y^p =z^p has no non-trivial integer solutions?
2. Given an elliptic curve E over the rational numbers, what can be said about the group of rational points of finite order on E?
These seem like very different problems, but, surprisingly, they share a common theme: they are both related to the existence of congruences between two types of modular forms, Eisenstein series and cusp forms. We will explain these examples, and discuss a new technique for giving quantitative information about these congruences (for example, counting the number of cusp forms congruent to an Eisenstein series). We will explain how this can give finer arithmetic information than simply knowing the existence of a congruence. This is joint work with Carl Wang-Erickson.

Research Area: Algebraic number theory and modular forms

### Coffee, Tea & Cookie Time

Wednesday, Nov 29 3:15 pm - 3:45 pm

Refreshments served in the Library Lounge

### Student Colloquium, Austin Rodgers, Purdue University, UNIV 101

Wednesday, Nov 29 4:30 pm - 5:20 pm

## Singular Loci of Sextic Curves

This talk will entertain the following question: Let C be a rational plane curve of degree 6. Let (m,n) be the degrees of the generators of the syzygy module. A general curve with (m,n) =(3,3) will have ten double points as singularities. The same is true for a general curve with (m,n) =(2,4). How can we distinguish these two sets of points geometrically? I will discuss some other algebraic distinctions between the two sets of curves and, time permitting, I'll touch on some of the potential methods used to provide a geometric distinction. Despite the technical language in the description of the problem, I hope to provide enough detail to show how down-to-earth the proof methods are for these kinds of results."

### Special Colloquium, Prof. Yat Tin (Raymond) Chow, UCLA, REC 317

Wednesday, Nov 29 4:30 pm - 5:20 pm

## TBA

Research Area: Numerical solutions to PDE, optimal control, and algorithms for optimization.

### Automorphic Forms and Representation Theory Seminar, Prof. Aaron Pollack, Duke University, BRNG 1260

Thursday, Nov 30 1:30 pm - 2:20 pm

## Title: TBA

### Coffee, Tea & Cookie Time

Thursday, Nov 30 3:15 pm - 3:45 pm

Refreshments served in the Library Lounge

### CCAM Lunch Seminar, Prof. David Gleich, Purdue University, LWSN B134

Friday, Dec 1 11:30 am - 12:20 pm

## TBD

### Coffee, Tea & Cookie Time

Friday, Dec 1 3:15 pm - 3:45 pm

Refreshments served in the Library Lounge

## Two Weeks

### Coffee, Tea & Cookie Time

Monday, Dec 4 3:15 pm - 3:45 pm

Refreshments served in the Library Lounge

### CCAM Seminar, Prof. Padmanabhan Seshaiyer , National Science Foundation, UNIV 103

Monday, Dec 4 4:30 pm - 5:30 pm

## Computational modeling, analysis and simulation of multi-physics applications in biological, bio-inspired and engineering systems

Abstract: In this talk, we will present modeling, analysis and simulation for nonlinear interaction of multi-physics applications described via coupled differential equation models that arise from examples such as flow-structure interactions to understand rupture of aneurysms and dynamics of micro-air vehicles as well as modeling infectious diseases to understand spread of Zika. Some theoretical and numerical results that validate the reliability and robustness of the computational methodology employed will also be presented.

### Special Colloquium, Prof. Wai-Tong (Louis) Fan, University of Wisconsin-Madison, REC 121

Monday, Dec 4 4:30 pm - 5:30 pm

## TBA

Research Area: Probability, stochastic analysis, biological modeling

### Colloquium Refreshments

Tuesday, Dec 5 3:00 pm - 3:30 pm

Refreshments served in the Library Lounge prior to Colloquium.

### Coffee, Tea & Cookie Time

Wednesday, Dec 6 3:15 pm - 3:45 pm

Refreshments served in the Library Lounge

### Coffee, Tea & Cookie Time

Thursday, Dec 7 3:15 pm - 3:45 pm

Refreshments served in the Library Lounge

### Coffee, Tea & Cookie Time

Friday, Dec 8 3:15 pm - 3:45 pm

Refreshments served in the Library Lounge

## Three Weeks

### Finals Week

Monday, Dec 11 - Friday, Dec 15

No regular refreshments during finals week.

### Automorphic Forms and Representation Theory Seminar, Prof. Ila Varma, Columbia University, BRNG 1260

Thursday, Dec 14 1:30 pm - 2:20 pm

Abstract