Kojève, Alexandre: Introduction to the Reading of Hegel. New York, 1969. p. 485:
Let us consider a gold ring. There is a hole and this hole is just as essential to the ring as the gold is; without the gold, the hole (which, moreover, would not exist) would not be a ring, but without the hole, the gold (which would none the less exist) would not be a ring either. But if one has found atoms in the gold, it is not at all necessary to look for them in the hole. And nothing indicates that the gold and the hole are in one and the same manner (of course, what is involved is the hole as ‘hole’ and not the air which is ‘in the hole’). The hole is a nothingness that subsists (as the presence of an absence) thanks to the gold which surrounds it. Likewise, Man who is Action could be a nothingness that ‘nihilates’ in being, thanks to the being which it ‘negates’.