\begin{picture}(30,20) \put(0,0){\circle*{2}} \put(30,0){\circle*{2}} \put(0,20... ...}} \put(20,10){\line(-2,1){20}} \bezier{150}(14,12)(15,15)(16,13) \end{picture}
$\textstyle \parbox{7cm}{ {\Huge\bf SEMINARIUM}}$
Zakładu Matematyki Dyskretnej
Wydziału Matematyki Stosowanej
AGH



We wtorek, 25 września 2100 roku, o godzinie 12:45
w sali 304, łącznik A-3-A-4, A G H



Hao LI
(Laboratoire de Recherche en Informatique, Orsay (Francja)



wygłosi referat pod tytułem:



Generalization of Dirac's theorem
on circumference of graphs


One of the most importent results in hamiltonian graph theory is due to Dirac: if $G$ is a graph on $n$ vertices such that its minimum degree is at least $n/2$, then $G$ is hamiltonian, i.e. has a cycle of length $n$.

Three generalization of the above theorem on which the author has contributed new results will be introduced in the talk.

The first generalization deals with the sufficient conditions of the hamiltonicity related to the neighborhood of independent vertices. The second concernes regular graphs. The last generalization is about Woodall's conjecture that is one of the 50 unsolved problems in the well-known book of Bondy and Murty Graph Theory with Applications. We have essentially proved this conjecture in 2000.

 
Serdecznie zapraszamy wszystkich chętnych !