Class 4: Inference

Selmer Bringsjord

• Logistics
  • Again: class pictorial roster, w/ email addresses & web sites$\dots$
  • Practice Midterm on web site_w
    • a new practice one coming, will be on web site
  • Deadlines: Project 1 one-class extension
    • was 5/27 for studio audience, no 6/1
    • want to check behvavior of functions up to chapter 14?
  • next time: resolution/review/Midterm
  • Anything else?

• Clarfification of mental objects
  • return to previous class slides
  • The Wise Man Puzzle
  • Getting careful about the alphabet and grammar of FOL_JR
  • using Hyperproof to do this

• Inference in the propositional calculus
  • c.j``The Lost Episode"
  • validity w/ truth tables to establish $\models$
  • rules of inference more efficient!

• The two central equation-schemas again:
  • KB $\models \alpha$
  • KB $\vdash_i \alpha$
• Selmer's World 3 _{Web,Hyperproof}

• Let's do some inferencing!
• Catching Colonel West
  • Web and AIMA for documentation
  • in OTTER
  • in Hyperproof

• But GMP not complete!$\ldots$
  • Problem, e.g.: $\forall x (\neg P(x) \Rightarrow Q(x))$
  • completeness; undecidability
    • Completeness: if KB $\models \alpha$ then KB $\vdash \alpha$
      • nuclear power plant emergency scenario again
    • Undecidability$\ldots$
• Did curiosity kill the cat?

• an implementation of full-blown logical agent: demo