$A = \left(-6,2,-7\right)$

$B = \left(8,10,6\right)$

$C = \left(3,8,5\right)$

What is the vector $\mathbf{v}$ whose tail and head are the midpoint of $\overline{AB}$ and the midpoint of $\overline{BC}$, respectively.

$\mathbf{v}$ =