LTMS: Truth Maintenance System
Incrementally maintains consequences of a propositional theory ? [Doyle 79; McAllester 80]
- incrementally manages addition and deletions from ?
- ideal for real-time propositional reasoning
Set ? contains propositional clauses
- a clause is disjunction of propositional literals
- a unit clause is a clause with exactly one disjunct
- a literal is a proposition or the negation of a proposition
¬ rain?? ¬ umbrella ? dry
- a clause can be read as an implication in different ways
rain?? umbrella ? dry
rain?? ¬ dry ??¬umbrella