A *(term) for systems that are not _(well-founded), meaning that they are not based strictly on a few independent principles.

This means that they have looser logical requirements: that they are merely self-consistent. These systems are very important in computer science despite appearances, since many types are non-wellfounded in nature, such as stream types or other iterative (non-recursive) types. Also, whole-system analyses usually rely on this perspective implicitly, since bootstrapping is otherwise not easily expressible.
