I need help with a part of Thurston's lecture note.
p.55~56 in the 4th lecture note states that when obtaining hyperbolic manifold by gluing polyhedra having some ideal vertices, the set of derivatives of the holonomy $\left\{| H'(\alpha)|\right\}$ determines the completion of a deleted neighborhood $N(v)$ of an ideal vertex $v$.
I really get in trouble seeing why this should be.
Is there any meterials in which I can find some hints? Any little one would be appreciated.