Class 3: First-Order Logic

Selmer Bringsjord

Misc. Logistical Issues

• Again: class pictorial roster, w/ email addresses & web sitesw
• TA Selim's info now in syllabus, w/ office hrsw
• My office hrs now in syllabus as wellw
• Go pagew
• The Lost Episode" (propositional calculus)

GUESS WHO?

Foundation for Logic-Based Agents

• Knowledge-Based Agent pseudo-codeh
• The wumpus-world sequence 6.2 6.4h
• Two central equation-schemas:
• KB
• KB

The Golden Concepts

• We've mentioned the three programming paradigms
• Two AI paradigms: logicist or symbolicist vs. connectionist or sub-symbolicist
• A list of key golden" concepts for logicist paradigm:
• soundness; proof; completeness; proof theory; interpretation; compositionality; deduction; validity ( ); satisfiability; unsatisfiability

Getting Help From Hyperproof

• HYPERPROOFHyperproof
• Selmer's World
• NBA 1999

 ENGLISH FOL Names: Selmer a Conrad c Olga b Katherine n1 Alexander n2 Predicates: x is rich Large(x) x is missing brain Tet(x) x is richer than y Larger(x,y) x lives further upstate than y BackOf(x,y) x lives between y and z Between(x,y,z) x is a parent of y Likes(x,y) x is a child Small(x) x is happy Happy(x) x and y live together SameRow(x,y)

Higher-Order Logic

• Hey, not so fast R&N!
• Define identity
• E.g., There is a notworthy property Selmer and Conrad share."
• SNePSLOG (possible 1 credit ind st investigation)
• The operator
• Basically same in Lisp

Some Lisp

• JR9000's gentle questions
• Ralph's not-so-gentle game
• True randomness? An automatic A?
• Collatz' function

Collatz' Function

• Conjecture: Starting from any positive integer n, repeated iteration of this function eventually produces the value 1.
• Lisp

Mental Objects

• The problem w/ straight FOL in connection w/ beliefs
• The detective story example
• A driving example (extemporaneous)
• Russell & Norvig's Treatment of Mental Objects - any good?
• CYC and Problem 8.15