The boundary of a fibered face of the magic 3-manifold and the   asymptotic behavior of the minimal pseudo-Anosovs dilatations
  Let $\delta_{g,n}$ be the minimal dilatation of pseudo-Anosovs defined on an orientable surface of genus $g$ with $n$ punctures. Tsai proved that for any fixed $g \ge 2$, the logarithm of the minimal dilatation $\log \delta_{g,n}$ is on the order of $\frac{\log n}{n}$. The main result of this paper is that if $2g+1$ is relatively prime to $s$ or $s+1$ for each $0 \le s \le g$, then $$\limsup_{n \to \infty} \frac{n \log \delta_{g,n}}{\log n} \le 2.$$ 
Eiko Kin, Mitsuhiko Takasawa
math.GT math.DS