Image Details
Caption: Figure 4.
Illustration of refinement of an element Kx into multiple finer elements ﹩\{{{\boldsymbol{k}}}_{{\boldsymbol{x}}}^{(j)}\}﹩ (prolongation; left to right) and coarsening of multiple elements into a single element (restriction; right to left) for the case with polynomial degree k = 2 and spatial dimensionality dx = 2.
© 2026. The Author(s). Published by the American Astronomical Society.