GC is interesting, because often times the concept of a reference is a concept of identity, whereas a pointer is a concept of location in the heap. Things like

GC is interesting, because often times the concept of a reference is a concept of identity, whereas a pointer is a concept of location in the heap. Things like reallocating GC that shuffle around location on the fly make this a bit easier since your references only pertain to identity, and the compression can be applied to estimating or validating the total number of identities won't exceed some maximum for a valid set of inputs to the program.