Occur Curve

E = Ω

${\mbox{Length}}(\gamma )=\sup \left\{\sum _{i=1}^{n}d(\gamma (t_{i}),\gamma (t_{i-1})):n\in \mathbb {N} {\mbox{ and }}a=t_{0}<t_{1}<\cdots <t_{n}=b\right\}.$