  Given Gupta and Belnap's general revision-theoretic treatment of circular definitions-of which their treatment of truth is a special case-one would expect revision-theoretic ideas to be applied to other concepts. Antonelli 1994b applies these ideas to non-well-founded sets: a non-well-founded set X can be thought of as circular, since, for some X0, …, Xn we have X ∈ X0 ∈ … ∈ Xn ∈ X. Chapuis 2003 applies revision-theoretic ideas to rational decision making.  Also, see Wang 2011 for a discussion of revision theory and abstract objects, and Asmus 2013 for a discussion of revision theory and vagueness.