> We present a formulation of the two algorithms that shows that they are in fact duals of each other. .... Using this framework, we show that all high-performance collectors (for example, deferred reference counting and generational collection) are in fact hybrids of tracing and reference counting.
...
> For every operation performed by the tracing collector, there is a corresponding "anti-operation" performed by the reference counting collector.
...
> We have shown that tracing and reference counting garbage collection, which were previously thought to be very different, in fact share the exact same structure and can be viewed as duals of each other.
> We present a formulation of the two algorithms that shows that they are in fact duals of each other. .... Using this framework, we show that all high-performance collectors (for example, deferred reference counting and generational collection) are in fact hybrids of tracing and reference counting.
...
> For every operation performed by the tracing collector, there is a corresponding "anti-operation" performed by the reference counting collector.
...
> We have shown that tracing and reference counting garbage collection, which were previously thought to be very different, in fact share the exact same structure and can be viewed as duals of each other.