25 February 2004
CS 3243 - Logical Agents (part 2)
14
Inference
nDefine: KB ├i α = sentence α can be derived from KB by procedure i
nSoundness: i is sound if whenever KB ├i α, it is also true that KB╞ α
nCompleteness: i is complete if whenever KB╞ α, it is also true that KB ├i α
nPreview: we will
define a logic (first-order logic) which is expressive enough to say almost anything of
interest, and for
which there exists a sound and complete inference procedure.
nThat is, the
procedure will answer any question whose answer follows from what is known by the KB.
• Is a set of
inference operators complete
and sound?
and sound?
Do the operators make conclusions
that aren’t always true?