Knowledge Systems Laboratory, Stanford
University
2
KR Language Components
uA logical formalism
8Syntax for wffs
8Vocabulary of logical
symbols (e.g., AND, OR, NOT, =>,
<=>)
8Interpretation semantics
for the logical symbols
E.g., “(=> A B)” is
true if and only if B is true or A is false.
uAn ontology
8Vocabulary of non-logical
symbols
>Relations, functions, constants
8Definitions of
non-primitive symbols
E.g., (<=>
(Bachelor ?x) (AND (Man ?x) (Unmarried ?x)))
8Axioms restricting the
interpretations of primitive symbols
E.g., (=> (Person ?x)
(Gender (Mother ?x) Female))
uA proof theory
8Specification of the
reasoning steps that are logically sound
E.g., From “(=> S1
S2)” and “S1”, conclude “S2”.