# Colloquia

## Thomas Polstra

When are two rings similar?

Date: 11/7/2017

Time: 4:30PM-5:30PM

Place: 315 Armstrong Hall

**Abstract:** Inspired by results of Samuel, Hironaka, Cutkosky and Srinivasan, and others which give criteria for rings which are quotients of a common power series ring to be isomorphic, it is natural to investigate when two rings, which are the quotient of a common power series ring, are ”similar.” In this talk we will discuss recent collaboration between the speaker and Ilya Smirnov which investigates this problem in rings of prime characteristic.

All are welcome.

## Misha Feldman

Short-time existence of smooth solutions for semigeostrophic system with variable Coriolis parameter.

Date: 10/12/2017

Time: 3:45PM-4:45PM

Place: 315 Armstrong Hall

**Abstract:** The semigeostrophic (SG) system is a model of large scale atmosphere/ocean flows. Previous results were obtained for the SG system with constant Coriolis parameter, by rewriting the problem in the "dual variables" and using Monge-Kantorovich mass transport techniques. A more physically realistic SG model has variable Coriolis parameter. Dual space is not available in this case. We work directly in the original "physical" coordinates, and show existence of smooth solutions for short time. This is a joint work with J. Cheng and M. Cullen.

All are welcome.

## WVU-China Graph Theory and Combinatorics Workshop

Every year, the Department of Mathematics at WVU hosts about 10 long term visitors sponsored by Chinese Scholar Council to conduct research in graph theory and combinatorics. To strengthen our collaboration with Chinese Graph Theory and Combinatorics Society, the Department of Mathematics will host a WVU-China Workshop on Graph Theory and Combinatorics on Thursday, September 14, 2017.

All are welcome and are invited to attend the workshop.

## Workshop Schedule

#### Location: Mountainlair Shenandoah Room

Time |
Speaker |
Title |
||||
---|---|---|---|---|---|---|

8:30am - 9:00am | Dr. Eddie Fuller, Chair of Mathematics, West Virginia University | Opening Remarks | ||||

9:00am - 9:50am | Xueliang Li, Nankai University | Conflict-free connections of graphs | ||||

10:00am - 10:50am | Kevin Milans, West Virginia University | First-Fit chain partitions in partially ordered sets | ||||

11:00am - 11:50am | Guanghui Wang, Shangdong University | Splitting graphs and digraphs | ||||

12:00pm - 1:30pm |
Lunch Break |
Lunch Break |
||||

1:30pm - 2:20pm | John Goldwasser, West Virginia University | Polychromatic colorings of complete graphs with respect to 1-regular and 2-regular subgraphs | ||||

2:30pm - 3:20pm | Mike Schroeder, Marshall University | Adding To and Removing From the Structure of Graph Decompositions | ||||

3:30pm - 4:20pm | Jerzy Wojciechowski, West Virginia University | General Matroids and the Almost Intersection Property | ||||

4:30pm - 5:20pm | Jiaao Li, West Virginia University | Nowhere-zero Flow Problems |

## Other Participants from China

- Professor Lingqi Zhao, College of Computer Science and Technology, Inner Mongolia University for Nationalities
- Bofeng Huo, Qinghai Normal University
- Liqiong Xu, Jimei University
- Yingzhi Tian, Xinjiang University

## Brief Introduction to the Speakers from China

#### Dr. Xueliang Li, Nankai University

- President for the Chinese Society of Combinatorics and Graph Theory
- Director of the Center for Combinatorics at Nankai University
- Dean of the School of Mathematics and Statistics, Qinghai Normal University
- Vice President of the International Academy of Mathematical Chemistry (IAMC)
- A member of editorial boards of many journals including Discrete Applied Mathematics, Graphs and Combinatorics, et al.
- President of Tianjin Society for Industrial and Applied Mathematics (TJSIAM)
- Council Member of the Chinese Mathematical Society (CMS)
- Executive Council Member of the Chinese Society for Industrial and Applied Mathematics (CSIAM)

#### Dr. Guiying Yan, Academy of Mathematics and Systems Science, Chinese Academy of Sciences(CAS)

- Vice Director of National Center for Mathematics and Interdisciplinary Sciences at CAS
- Secretary-General of China Society for Industrial and Applied Mathematics (CSIAM)

#### Dr. Guanghui Wang: School of Mathematics, Shandong University

- Assistant Dean of School of Mathematics, Shandong University
- Deputy General Secretary of Graph Theory and Combinatorics Branch of Operations Research Society of China
- Director of Young Crew Management Board of the Society

## Hung Tran

Some selection problems in the theory of viscosity solutions

Abstract: I will explain some interesting selection problems in nonlinear PDEs. The basic question is about how to select one good solution out of many reasonable ones. A question of this type led to the whole theory of viscosity solutions in 1980s. Then I will focus on the vanishing discount problem and describe the main results, which solve an open question also in 1980s. This is a joint work with Ishii and Mitake.

Date: 4/28/2017

Time: 3:30PM-4:30PM

Place: 315 Armstrong Hall

All are welcome.

## David Offner

Polychromatic Colorings on Hypercubes, Complete Graphs, and Integers

Abstract: Given a set S, and a set T of subsets of S, a coloring of the elements of S is called T -polychromatic if every set in T contains an element of every color. Let polyT (S) be the largest n for which there is a T -polychromatic coloring of S with n colors. This talk introduces theorems and open problems on the value of polyT (S) in three settings:

• S is the set of edges of a hypercube, and T is the set of all subgraphs isomorphic to

a given graph H.

• S is the set of edges of a complete graph, and T is the set of all regular spanning

subgraphs of a given degree.

• S is the set of integers, and T is the set of translates of a given finite set.

Date: 4/26/2017

Time: 3:30PM-4:30PM

Place: 315 Armstrong Hall

All are welcome.

## Juan Pablo Mejia-Ramos

Developing valid and reliable measures to assess students' comprehension of the proofs that they read

Abstract: In this talk I will focus on the assessment of undergraduate students' reading comprehension of mathematical proofs, discussing a research program aimed at developing and validating reliable proof comprehension tests. I will present findings on students performance on three of these tests and discuss what we can learn from using this kind of measures in the mathematics classroom and in mathematics education research.

Date: 4/21/2017

Time: 2:30PM-3:30PM

Place: 315 Armstrong Hall

All are welcome.

## Deborah Chun

Matroids and wilder things: Polymatroids and Delta-matroids

Abstract: Matroids will be introduced in this talk. I will give an example of a result for general matroids, which has interesting corollaries in more specialized classes of structures, like graphs. I will also discuss two generalizations of matroids. In polymatroids, I will give a conjecture from Vertigan, that, if true, has an important corollary in matroid theory. That is, it gives us Rota's conjecture. In delta-matroids, I will present a splitter theorem.

Date: 4/13/2017

Time: 4:00PM-5:00PM

Place: 315 Armstrong Hall

All are welcome.

## Hiroki Matsui

Thick subcategories of modules and characterizations of local rings

Abstract: View

Date: 4/12/2017

Time: 4:00PM-5:00PM

Place: 313 Armstrong Hall

All are welcome.

## C.F. Jeff Wu

From real world problems to esoteric research: examples and personal experience

Abstract: Young (and some not-so-young) researchers often wonder how to extract good research ideas and develop useful methodologies from solving real world problems. The path is rarely straightforward and its success depends on the circumstances, tenacity and luck. I will use three examples to illustrate how I trod the path. The first involved an attempt to find optimal growth conditions for nano structures. It led to the development of a new method “sequential minimum energy design (smed)”, which exploits an analogy to potential energy of charged particles. After a few years of frustrated efforts and relentless pursuit, we realized that smed is more suitable for generating samples adaptively to mimic an arbitrary distribution rather than for optimization. The main objective of the second example was to build an efficient statistical emulator based on finite element simulation results with two mesh densities in cast foundry operations. It eventually led to the development of a class of nonstationary Gaussian process models that can be used to connect simulation data of different precisions and speeds. The third example is about sequential design that works well for small samples in sensitivity testing. I will describe three major papers in a span of 30 years and how each paper had one new idea that inspired the next paper. In each example, the developed methodology has broader applications beyond the original problem. I will explain the thought process in each example. Finally, I will share some secrets about a “path to innovation”.This talk will have many illustrative examples, and should be accessible to graduate students.

Date: 4/06/2017

Time: 3:30PM-4:30PM

Place: Evansdale Crossing 414

All are welcome.

## Hiroki Matsui

Thick subcategories of modules and characterizations of local rings

Abstract: View

Date: 4/05/2017

Time: 4:00PM-5:00PM

Place: 315 Armstrong Hall

All are welcome.

## Pages