A truth maintenance system (TMS) is a form of non-monotonic reasoning. A TMS links potential assertions (such as 'it is cold' and 'it is winter') and attempts to maintain a coherent set of beliefs about theor truth. Some are given as facts, others may have their truth determined by assuming defaults where facts are unknown (for example if it is winter one assumes it is also cold). As new facts arise some of the previous truth values may need to change, for example a temperature reading may show it is avctually an unusually warm winter's day and hence the truth assigned to 'it is cold' changes.
Used in Chap. 3: page 29
Also known as TMS