I've been reading Huisken's paper on his distance comparison principle and he remarked that in particular his theorem rules out the formation of type II singularities. These are singularities where in particular cusps form. Why is this true? For reference I will include his principle below

Huisken's Distance Comparison Principle

Let $F:\Gamma\times[0,T]\rightarrow\mathbb{R}^2$ be a smooth embedded solution of the curve shortening flow (1.1). Let $\Gamma\neq S^1$, such that $l$ is smoothly defined on $\Gamma\times \Gamma$. Suppose $d/l$ attains a local minimum at (p,q) in the interior of $\gamma\times\gamma$ at time $t_0\in[0,T]$. Then$$\frac{d}{dt}(d/l)(p,q,t_0)\geq0$$ with equality if and only if $\Gamma$ is a straight line.

Note: $$d(p,q,t)=|F(p,t)-F(q,t)|$$ and $$l(p,q,t)=|\int_p^qds_t|$$


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