  In this paper we study the Taylor series of an operator-valued function
related to the differential of the exponential map. For a smooth manifold
$\mathcal{M}$ with a torsion-free affine connection the operator
$\mathcal{E}_p(v)$ acting on the space $T_p\mathcal{M}$ is defined to be the
composition of the differential of the exponential map at $v\in T_p\mathcal{M}$
with parallel transport to $p$ along the geodesic. The Taylor series of
$\mathcal{E}_p$ as a function of $v$ is found explicitly in terms of the
curvature tensor and its high order covariant derivatives at $p$.
