1# Selecting Parts of Meshes (DMLabel) 2 3The `DMLABEL` object is used to mark pieces of a mesh or `DM`, for example to indicate that a boundary condition should hold on that section. 4Markers are integers, so it can be seen as a multimap between integers and mesh pieces. 5 6Insertion is amortized $O(1)$ since hash tables are used, 7but each bin is then sorted so that extraction into sorted levels is also $O(1)$. The total cost should be $O(N log N)$ for $N$ entries. 8