Footnotes
-  (1)
 - Immutable bitsets of elements in the range of 0 to 127 
optimize the array away and store the bits directly in a one or two Long fields.
  
 -  (2)
 - The branching factor of a tree or a graph is the number of children at each node.
  
 -  (3)
 - Assuming bits are densely packed
  
 -  (4)
 - Assuming bits are densely packed
  
 -  (5)
 - An exception to this are arrays: Applying delayed operations
on arrays will again give results with static type Array.