CS676: Knowledge Representation Fall, 1997

Homework 3
Due at start of class, October 16, 1997

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


  1. Using the Rules of Inference of the FR system, as given in Chapter 3.2 of the text, prove

    ((P -> Q) & (Q -> R)) -> (P -> R)

  2. Prove that (L(A) & L(A => B)) => L(B) is valid in modal logics.

  3. Prove that (L(A) & (A => B)) => L(B) is not valid in modal logics.


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