Chennai Mathematical Institute


2.00 pm, Lecture Hall 2
Graph homomorphisms from a topological point of view

Shuchita Goyal
IIT Bombay.


Finding the chromatic number of a graph has always been an interesting problem in Graph Theory. In this talk, we will see how a graph $G$ gives rise to a topological space which contains crucial information about the chromatic number of $G$.

In particular, we will see how Lovasz proved that the chromatic number of the Kneser graph, $KG_{n,k}$, is $ n-2k+2$ using topological tools. For a graph $G$, we will also explore the topology of the space of $H$-colourings of $G$ and its relations with the chromatic number of $G$ and $H$.