 p39, line 2. $= \bar{\tau}\bar{\mathbf{\Omega}} l  ...$
 p39, line 3. $\mathbf{t}_0=\mathbf{t}(0)$. It is OK, but the latter is more consistent.
 p39, three lines before Lemma 5.2. $t_0$ can be $t$. There is no reason for a suffix $0$.
 p41, line 7. ``Helix $\mathcal{H}$ exists if and only if the conjunction of those two equalities holds.'' What does this mean ?
 p42, line 5, add the period at the end of the sentence.
 p42, (A21) and (A24) is used to prove `which is equivalent to'.
 p43, three lines before (A38). Remove `plus' between $\sin\varphi_*)$ and $\big((1t_0)$.
 p44, line 7, $\varphi_* \cot \frac{\varphi_*}{2}  2<0$ is derived straightforwardly from $x < \tan x$ for $0<x<\frac\pi2$.
 p.. signature of last formula.
