week 11: belief revision
week 12: first-order logic
CNF: conjunction of clauses.
p -> q <=> not p V q;
Special kinds of clauses:
definite clause: exactly one is positive.
horn clause: at most one is positive.
goal clause: no positive literals.
Levi identity B∗φ:= (B÷¬φ) +φ.
Belief revision can be defined as first removing any inconsistency with the incoming information and then adding the information itself.
First-order Logic
Propositional Logic: Reasoning about situations using combinations of simple facts(with “and”, “or”, “not” etc). The structure of these facts was not analyzed further.
first-order Logic: First-order Logic looks at the internal structure of basic facts, especially, the objects that occur, the properties of these objects, and their relations to each other.
