Homework 2
Due at start of class, September 28, 1999
Stuart C. Shapiro
Department of Computer Science
State University of New York at
Buffalo
Formalize the following argument in Classical Predicate Logic by giving the syntax and intensional semantics of the atomic symbols, and show a natural deduction style derivation of the conclusion from the assumptions.
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 if B believes A, he takes evasive action, but if he doesn't believe him, he doesn't take evasive action. 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. Therefore, if Bob thinks that Larry is a liar and there's danger, Bob gets injured.