- Series
- Graph Theory Seminar
- Time
- Thursday, September 28, 2017 - 1:30pm for 1 hour (actually 50 minutes)
- Location
- Skiles 005
- Speaker
- Jie Ma – University of Science and Technology of China
- Organizer
- Xingxing Yu

In this talk we will discuss some Tur\'an-type results on graphs with a given circumference.
Let $W_{n,k,c}$ be the graph obtained from a clique $K_{c-k+1}$
by adding $n-(c-k+1)$ isolated vertices each joined to the same $k$ vertices of the clique,
and let $f(n,k,c)=e(W_{n,k,c})$.
Kopylov proved in 1977 that for $c
a recent result of Li et al. and independently, of F\"{u}redi et al. on non-Hamiltonian graphs.
Moreover, we prove a stability result on a classical theorem of Bondy on the circumference.
We use a novel approach, which combines several proof ideas including a closure operation and an edge-switching technique.