Distributed Garbage Collection (DGC) in computing is a particular case of Garbage Collection

Garbage collection (computer science)

In computer science, garbage collection is a form of automatic memory management. The garbage collector, or just collector, attempts to reclaim garbage, or memory occupied by objects that are no longer in use by the program...

where references to an object can be held by a remote client.

DGC algorithms typically rely on a time lease set on the Object; it's the Remote Client's stub object task to periodically renew the lease on the remote object. If the lease is expired, the GC engine can safely assume that the Remote Client is no longer interested in the Object, hence proceed to Garbage Collection.