My question is similar to
The mean of points on a unit n-sphere $S^n$.
I have a unit n$n$-sphere $S^n$ and a set $P$ of points lying on its surface. I use geodesic distance metric $d(p,q)=\arccos(pq^T)$. Additionally I have a guarantee that all of my points are positive (unit vectors with all coordinates greater than or equal to 0).
The task is to find a centroid of those points, whose uniqueness is guaranteed because all points are positive.
In such case, does the centroid always coincide with the normalised arithmetic mean of the points? Formally $$\mu_{arithmetic} = \frac{1}{|P|}\sum_{p\in P}p$$ $$\mu_{geodesic}=\arg\min_c\sum_{p\in P}d(p,c)^2$$\begin{gather*} \mu_\text{arithmetic} = \frac{1}{\lvert P\rvert}\sum_{p\in P}p \\ \mu_\text{geodesic}=\arg\min_c\sum_{p\in P}d(p,c)^2. \end{gather*} Question: do we have $$\mu_{geodesic}=\frac{\mu_{arithmetic}}{||\mu_{arithmetic}||}$$$$\mu_\text{geodesic}=\frac{\mu_\text{arithmetic}}{\lVert\mu_\text{arithmetic}\rVert}?$$