The complete bipartite graph Km, n is the simple undirected graph with m + n vertices split into two sets V1 and V2
(|V1| = m, |V2| = n)
such that vertices x, y share an edge if and only if x is in V1 and y is in V2. For example, K3, 4 is the following graph, where V1 is the top row of vertices and V2 is the bottom row.
SEE SCREENSHOT :)

Question

The complete bipartite graph Km, n is the simple undirected graph with m + n vertices split into two sets V1 and V2
(|V1| = m, |V2| = n)
such that vertices x, y share an edge if and only if x is in V1 and y is in V2. For example, K3, 4 is the following graph, where V1 is the top row of vertices and V2 is the bottom row. 
SEE SCREENSHOT :)

anonymous · Answer

attachment

anonymous · Answer

K_m,n has chromatic 2. so the answer is 2

anonymous · Answer

|dw:1367548394652:dw| you need just 2 color to fill the nodes

anonymous · Answer

Cool, thank you so much...great explanation :)