An AutocatalyticSet is a chain of catalyzed reactions that folds back on itself.

Suppose that A catalyzes a reaction that increases the concentration of B, which I will denote as
   A -> B
Then an AutocatalyticSet is a reaction such that:
   A -> B -> ... -> N -> A
Or
   A ->* A
''Yes, I just wanted to beat the reader over the head with its sequential nature. Specifically, suppose there are two AutocatalyticSet''''''s AC1 and AC2, so that:''

   AC1 = A->B->A
   AC2 = A->C->A
''These are different AutocatalyticSet''''''s. I'm not sure that the more terse notation sufficiently reveals their difference.''

See
http://en.wikipedia.org/wiki/Autocatalytic_set