or Pettie \cite{pettie:ackermann}.
\qed
+Similarly to the Iterated Jarn\'\i{}k's algorithm, this bound is actually linear for classes of graphs
+that do not have density extremely close to constant:
+
+\cor
+The Optimal MST algorithm runs in linear time whenever $m\ge n\cdot a(k,n)$ for any fixed~$k$.
+
+\proof
+Combine the previous theorem with Lemma \ref{alphaconst}.
+\qed
+
\rem
It is also known from \cite{pettie:optimal} that when we run the Optimal algorithm on a~random
graph drawn from either $G_{n,p}$ (random graphs on~$n$ vertices, each edge is included with probability~$p$