CS676: Knowledge Representation Fall, 1997

Homework 4
Due at start of class, November 13, 1997

Stuart C. Shapiro
Department of Computer Science
State University of New York at Buffalo

Formalize the following argument in SNePSUL or SNePSLOG.

No person believes what is said by anyone he believes to be a liar. When there's danger, if person A warns person B, then B takes evasive action if and only if he believes A. If there's danger, anyone who doesn't take evasive action gets injured. Whenever there's danger, Larry warns Bob. Larry warns Bob by saying something to him. If someone says something, you believe what they say if and only if you believe them. Bob is a person. Larry is a person. Bob thinks that Larry is a liar. There's danger. Therefore, Bob gets injured.

For extra credit, run SNePS on your formalization.

Stuart C. Shapiro <shapiro@cs.buffalo.edu>