1. CSE4/563: Knowledge Representation Recitation September 15, 2010 “In activities other than purely logical thought, our minds function much faster than any computer yet devised.” --Daniel Crevier

2. Brief Unix Tutorial

3. Questions/Concerns? http://www.cse.buffalo.edu/~shapiro/Courses /CSE563/2010/Homeworks/hw0.pdf http://www.cse.buffalo.edu/~shapiro/Courses /CSE563/2010/Homeworks/hw0.pdf

4. Logical Entailment A 1,…, A n ╞ L B

5. Logical Entailment A 1,…, A n ╞ L B – Example: A 1 = Tom drives  Betty is the passenger A 2 = Tom drives A 1, A 2 ╞ Betty is the passenger

6. Logical Entailment A 1,…, A n ╞ L B – Example: A 1 = Tom drives  Betty is the passenger A 2 = Tom drives A 1, A 2 ╞ Betty is the passenger ╞ B

7. Well Formed Propositions Every atomic proposition is a wfp. 2. If P is a wfp, then so is (~P). 3. If P and Q are wfps, then so are (a) (P ^ Q) (b) (P v Q) (c) (P => Q) (d) (P Q) 4. Nothing else is a wfp.

8. Semantic Properties of WFPs Satisfiable? Contingent? Valid? Unsatisfiable? Contradictory?

9. Denotation Example from Notes Notes p. 48

10. Logical Entailment A 1,…, A n ╞ L B – Example: A 1 = Tom drives  Betty is the passenger A 2 = Tom drives A 1, A 2 ╞ Betty is the passenger ╞ B – Example: ╞ (P or ~P)

11. Semantic Tableau http://www.cse.buffalo.edu/~shapiro/Courses /CSE563/Slides/chap2.pdf p51 http://www.cse.buffalo.edu/~shapiro/Courses /CSE563/Slides/chap2.pdf

12. Model-Finding Refutation TDB=>TD, TD=>BP, ~(TP^BP) ╞ ~(TDB ^ TP)