Editing Turán's theorem (section)

==Statement==
Turán's theorem states that every graph <math>G</math> with <math>n</math> vertices that does not contain <math>K_{r+1}</math> as a subgraph has at most as many edges as the Turán graph <math>T(n,r)</math>. For a fixed value of <math>r</math>, this graph has<math display="block">\left(1-\frac{1}{r}+o(1)\right) \frac{n^2}{2}</math>edges, using [[Little o notation|little-o notation]]. Intuitively, this means that as <math>n</math> gets larger, the fraction of edges included in <math>T(n,r)</math> gets closer and closer to <math>1-\frac{1}{r}</math>. Many of the following proofs only give the upper bound of <math>\left(1-\frac{1}{r}\right)\frac{n^2}{2}</math>.{{r|az}}