# Colloquia

## Seyfi Turkelli

Counting Field Extensions with Bounded Discriminant

Abstract:In this talk, I will talk about the problem of counting fields with bounded discriminant. After introducing the problem and surveying the important related results, I will talk about its historical connection with Fermat’s Last Theorem, and its important place in the research in number theory. I will conclude the talk with a recent result and the sketch of its proof.

Date: 3/15/2017

Time: 3:00PM-4:00PM

Place: 313 Armstrong Hall

All are welcome.

## RUME Seminar

Student-centred teaching with the Extreme Apprenticeship method

Drs. Johanna Rämö and Jokke Häsä from the University of Helsinki will present

Abstract: Extreme Apprenticeship is a novel student-centred teaching method for large classes with hundreds of students. Its theoretical background is in situated view on learning and Cognitive Apprenticeship. In XA, students participate in activities that resemble those of professional mathematicians. The key elements are instructional scaffolding and continuous bi-directional feedback. Students are guided in their work by undergraduate/graduate TAs. In our talk, we introduce the XA method, and tell how the professional development of TAs has been organised.

Date: 3/3/2017

Time: 2:30PM-3:30PM

Place: 315 Armstrong Hall

All are welcome.

## Tokuji Araya

Topological approach to modeling spatial cognition

Date: 2/8/2017

Time: 4:00PM-5:00PM

Place: 315 Armstrong Hall

Abstract:The Auslander-Reiten quiver is one of the crucial tools to investigate the category of finitely generated modules over noetherian rings. It is an oriented graph whose vertices are indicated by indecomposable modules, and whose arrows are indicated by irreducible homomorphisms. In this talk, we will recall the notion of Auslander-Reiten quiver and calculate some examples.

All are welcome.

## Yuri Dabaghian

Topological approach to modeling spatial cognition

Date: 2/1/2017

Time: 9:00AM-11:00AM

Place: 401 Engineering Science Building

All are welcome.

## Yu Hu

Relating the connectivity of neural networks to dynamics: the effect of motifs and connecting network models across scales

Date: 1/30/2017

Time: 5:00PM-7:00PM

Place: 301 Health Sciences Center Biomedical Research Building

All are welcome.

## Liu and Zhang

There will be two speakers for this event.

Professor Liu, Hubei University, will speak on "Some Conjectures on the Signless Laplacian Spectral Radius of Graphs".

Professor Zhang, Xia'Meng University, will speak on "The Surviving Rate of Graphs for Firefighter Problem"

Liu Abstract: Here

Zhang Abstract: Here

Date: 11/18/2016

Time: 3:30PM-5:30PM

Place: 315 Armstrong Hall

## Xiangqian Zhou

Induction for "4-connected" Matroids and Graphs

A matroid M is a pair (E,I) where E is a ﬁnite set, called the ground set of M, and I is a non-empty collection of subsets of E, called independent sets of M, such that (1) a subset of an independent set is independent; and (2) if I and J are independent sets with |I|

Abstract: Here

Date: 10/28/2016

Time: 3:30PM-4:30PM

Place: 315 Armstrong Hall

## Yue Zhao

Vizing's conjectures and related problems

In 1965, Vizing proposed three conjectures about edge chromatic critical graphs which are Vizing’s Planar Graph Conjecture, Vizing’s 2-Factor Conjecture and the conjecture about the size of edge chromatic critical graphs. In 1968, Vizing proposed the Independence Number Conjecture that is a weaker conjecture than his 2-factor conjecture. In this talk, we will focus on the above four conjectures and talk about the progress and some related problems.

Date: 10/27/2016

Time: 3:30PM-4:30PM

Place: 315 Armstrong Hall

## Sean Sather-Wagstaff

Finiteness Conditions in Algebra

Mathematical objects that satisfy finiteness conditions are frequently easier to work with than arbitrary objects. For instance, finite dimensional vector spaces are nicer in many ways than infinite dimensional ones. In this talk, I will discuss a variety of classical finiteness conditions in algebra and other areas: what they are and why they are useful. I will conclude with some new results answering a modified version of a question of Huneke about finiteness of associated primes in local cohomology.

This talk will be accessible to graduate students.

Date: 10/25/2016

Time: 4:00PM-5:00PM

Place: 315 Armstrong Hall

## Zhi-Hong Chen

Cycles of claw-free graphs and Catlin's reduction method

In the study of cycles of claw-free graphs,

Ryj\'{a}\u{c}ek developed a very nice closure concept: For a connected claw-free graph $H$, there is a $K_3$-free graph $G$ such that its closure $cl(H)=L(G)$ and for each cycle $C_0$ in $L(G)$, there exists a cycle $C$ in $H$ with $V(C_0)\subseteq V(C)$. A theorem by Harary and Nash-Williams shows that a line graph $L(G)$ has a Hamiltonian cycle if and only if $G$ has a dominating closed trail.

Thus, to find a cycle in a claw-free graph $H$ can be reduced to finding a closed trail in the preimage $G$ of the line graph of $L(G)$, where $L(G)=cl(H)$.

In this talk, I will discuss applications of Catlin's reduction method to the study of cycles in claw-free graphs and discuss new results and solutions of some conjectures on claw-free graphs that we obtained recently.

Date: 10/14/2016

Time: 3:45PM-4:45PM

Place: 315 Armstrong Hall

## Pages