[battle-racket]

> It acts like a dual construction to a tracing GC in many cases

yeah one of the most helpful realizations I’ve read is that tracing and ref counting are essentially two formulations of the same problem - one is finding objects that are alive (by tracing), and the other is finding things that are dead (i.e. their ref counts reach zero). and of course, every object is either dead or alive!

[fc417fc802]

It's a useful realization but the follow on (unfortunately rather popular) claim that this inverse relation makes them the same thing is clearly wrong. They exhibit entirely different performance characteristics in places where it matters.