Update paper.md

Co-authored-by: Sandro Elsweijer <[email protected]>

paper.md

@@ -146,7 +146,7 @@ supported.
 ($\text{k}_{\text{0}}$, $\text{k}_{\text{1}}$) distributed over three parallel
 processes p0 to p2. The SFC is represented by a black curve tracing only the
 finest elements (leafs) of each tree. Right: Sketch of the associated
-mixed shape mesh refined up to level three.\label{fig:SpaceFillingCurves}](pics/t8code_sfc_hybrid.png)
+mixed shape mesh refined up to level three. Bottom left: The elements saved by p1 and the associated ghost  elements (non process local neighbors). \label{fig:SpaceFillingCurves}](pics/t8code_sfc_hybrid.png)
 
 # Performance