Editing Interval graph (section)

==Definition==
An interval graph is an undirected graph {{mvar|G}} formed from a family of intervals
:<math>S_i,\quad i=0,1,2,\dots</math>
by creating one vertex {{mvar|v{{sub|i}}}} for each interval {{mvar|S{{sub|i}}}}, and connecting two vertices {{mvar|v{{sub|i}}}} and {{mvar|v{{sub|j}}}} by an edge whenever the corresponding two sets have a nonempty intersection. That is, the edge set of {{mvar|G}} is
:<math>E(G)=\{(v_i,v_j)\mid S_i\cap S_j\ne\emptyset\}.</math>
It is the [[intersection graph]] of the intervals.