Colloquia
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
Liang Hong
Credibility Theory without Tears
After a brief introduction of the actuarial science program at Robert Morris University, I will introduce the basic framework of Bayesian statistics and classical theory of credibility theory, a topic heavily tested on SOA's Exam C.
The last part of the talk will give the latest development in credibility theory; this work was done by my colleague (Dr. Ryan Martin, at North Carolina State University) and me, and our project was jointly sponsored by the Casualty Actuarial Society and Society of Actuaries through 2015 Individual Grant. The technical details are kept to a minimum. Therefore, the talk is accessible to anyone with a background in calculus-based probability theory, that is, the basic topics on Exam P.
Dr. Hong received his PhD in mathematics from Purdue University. He has received grants from the Casualty Actuarial Society (CAS), Society of Actuaries (SOA), and State Farm Insurance Company; and he has given research talks at several Center for Actuarial Excellence (CAE) schools including Drake University, Georgia State University, Temple University, University of Waterloo, University of Wisconsin, Madison.
Date: 9/23/2016
Time: 12:30PM-1:20PM
Place: 121 Armstrong Hall
Hao Li
On the g-extra connectivity of $3$-ary $n$-cube networks
Let $G$ be a connected graph and let $F$ be a set of vertices.
The $g$-extra connectivity of $G$ is the cardinality of a minimum set
$F$ such that $G-F$ is disconnected and each component of $G-F$ has at
least $g+1$ vertices. The $g$-extra connectivity is an important
parameter to measure the reliability and fault tolerance ability of
large interconnection network of parallel computing systems.
In 2011, the $g$-extra connectiviy for $g=1,2$ of 3-ary $n$-cubes are
gotten by Zhu et al. The 3-extra connectivity of 3-ary $n$-cubes are
given by Gu and Hao in 2014. Here, we determine the $g$-extra
connectivity of 3-ary $n$-cubes for $0\le g \le 2n$.
Date: 8/25/2016
Time: 3:45PM-4:45PM
Place: 315 Armstrong Hall
Xiao-Dong Zhang
Some Extremal Graph Results with Degree Sequences
As it is said in the book \Extremal Graph Theory" by Bollobas, in extremal graph theory one is interested in the relations between the various graph variants, such as order, size, connectivity, minimum degree, maximum degree, chromatic number and diameter, and also in the values of these in-variants which ensure that the graph has certain properties. In this talk, we introduce some progresses and results on graph variants, such as spectral radius, Laplacian spectral radius, the average distance, and the number of sub-trees for a class of graphs with given degree sequences, and we also introduce some related open problems.
Professor Xiao-Dong Zhang's Website
Date: 8/23/2016
Time: 3:30PM-4:30PM
Place: 315 Armstrong Hall
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